WO2015110630A1 - Efficient multicasting method and system applying direct device-to-device connections - Google Patents
Efficient multicasting method and system applying direct device-to-device connections Download PDFInfo
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- WO2015110630A1 WO2015110630A1 PCT/EP2015/051480 EP2015051480W WO2015110630A1 WO 2015110630 A1 WO2015110630 A1 WO 2015110630A1 EP 2015051480 W EP2015051480 W EP 2015051480W WO 2015110630 A1 WO2015110630 A1 WO 2015110630A1
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- channel quality
- user devices
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W76/00—Connection management
- H04W76/10—Connection setup
- H04W76/14—Direct-mode setup
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/50—Allocation or scheduling criteria for wireless resources
- H04W72/54—Allocation or scheduling criteria for wireless resources based on quality criteria
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W76/00—Connection management
- H04W76/40—Connection management for selective distribution or broadcast
Definitions
- the invention relates to a method and system for providing data to a plurality of user devices. More specifically, the invention relates to an efficient method and system for multicasting data to a group of devices being enabled to establish device-to-device connections.
- Multicasting in a traditional and commonly known form pertains to a method for delivering data comprising one or more data packets to a group of user devices simultaneously in a single transmission from a source. If a network is involved, copies of the data packets are created in network elements, such as routers, when required by the topology of the network.
- IP multicast which is often employed in Internet Protocol (IP) applications for streaming media and Internet television
- the multicast occurs at the IP routing level, where multicast-enabled IP routers copy and forward, as far as needed, IP data packets addressed to a multicast destination address.
- MBMS Multimedia Broad- cast/Multicast Service
- a Multimedia Broad- cast/Multicast Service is known which is designed to deliver broadcast and multicast services from a single base station or group of base stations to multiple user devices receiving the same content.
- the primary benefit of MBMS is more efficient utilization of network and frequency spectrum resources by ensuring that content to be delivered to several user devices uses, on the path from the source via one or more base stations to user devices, a single channel or bit stream rather than individual bit streams to each user device.
- a user of a user device terminal, UE
- the subscription and group joining for the multicast mode services could be done by the mobile network operator, the user or a separate service provider.
- LTE Long Term Evolution
- LTE Advanced Long Term Evolution Advanced
- LTE Advanced also known as the 4G (i.e. fourth generation) mobile communications standard
- 4G fourth generation
- mobile user devices terminals
- terminal mobile user devices
- UMTS/HSPA also known as 3G
- Modulation and coding scheme selection in multimedia broadcast of a single frequency network-enabled long-term evolution network by A. Alexiou et al., published in Int. J. Commun. Syst. (201 1 ) discloses methods in LTE systems to improve spectral efficiency by selecting modulation and coding scheme (MCS).
- MCS modulation and coding scheme
- the modulation and coding scheme is expressed as an index in a predefined list of several combinations of modulation and coding that may be used in the multicast transmission from a base station to the user devices.
- the applied modulation determines the number of bits that is carried in one transmitted symbol (examples of modulation include QPSK, 16QAM en 64QAM).
- redundancy is added to the data bits to be transmitted, thus increasing the total number of bits to be transmitted.
- a higher channel quality allows a higher order modulation to be applied, e.g. 16QAM instead of QPSK (with a certain bit error ratio as a parameter).
- the applied coding rate determines the ratio (smaller than one, examples include 4/5, 1/2, 1/3) of the number of data bits to be transmitted over the total number of bits to be transmitted.
- a higher channel quality also allows less redundancy to be applied, e.g. 4/5 or 1/2 instead of 1/3 (with a certain block error ratio as a parameter).
- An ordered list of channel qualities may be mapped onto a correspondingly ordered list of combinations of a particular modulation and a particular coding rate (with a certain block error ratio as a parameter).
- the spectral efficiency for transmission to a single user device is determined by the data rate at which data can be successfully transmitted over a given bandwidth of the wireless radio interface.
- the spectral efficiency is determined by the data rate averaged over the user devices.
- SINR signal-to-interference plus noise ratio
- the spectral efficiency is directly related to the MCS selected for the transmission and that the MCS is selected from a pre-defined list of modulation and coding schemes based on signal-to-interference plus noise ratio (SINR) values as measured by the terminals.
- SINR-to-MCS mapping a certain expected maximum or target block error rate (BLER, e.g. 10%) is used as a parameter.
- BLER target block error rate
- aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, a software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," “module” or “system”. Functions described in this disclosure may be implemented as an algorithm executed by a microprocessor of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.
- the computer readable medium may be a computer readable signal medium or a computer readable storage medium.
- a computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.
- a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
- a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof.
- a computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
- Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless (using electromagnetic and/or optical radiation), wired, optical fiber, cable, etc., or any suitable combination of the foregoing.
- Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java(TM), Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages.
- the program code may execute entirely on a user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server.
- the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
- LAN local area network
- WAN wide area network
- Internet Service Provider an Internet Service Provider
- These computer program instructions may be provided to a processor, in particular a microprocessor or central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
- a processor in particular a microprocessor or central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
- CPU central processing unit
- These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
- the computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
- each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s).
- the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the functions noted in the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.
- the present disclosure presents a method for multicasting data for at least a first user device and a second user device from a telecommunications network over a wireless radio interface.
- the first user device and the second user device are enabled to establish a connection with the telecommunications network over the wireless radio interface and to establish a direct wireless connection with each other.
- the registration of the capability and/or enablement for establishing direct connections may be a step in the disclosed method.
- the method comprises a step in the telecommunications system of receiving channel quality information from the first user device and the second user device, the channel quality information being indicative of a wireless channel quality of a wireless channel between the telecommunications network and the first user device and the second user device, respectively.
- the channel quality information may comprise any, e.g. quantitative, information that is indicative of the quality of the radio channel or from which quantitative information of the radio channel quality to a user device can be derived.
- the channel quality information may be an estimate, an approximation or a representation of the actual channel quality.
- the channel quality information enables, possibly by derivation, to distinguish between poorer and better channel qualities experienced by the user devices.
- the user devices may report the channel quality information to the telecommunications network, e.g. periodically and/or in response to a request received from the network, using e.g. CQI report.
- the user device In LTE telecommunications networks for a unicast transmission from the telecommunications network to a user device, the user device periodically reports the channel quality indicator (CQI) to the eNodeB via the Physical Uplink Control Channel (PUCCH) or, if Physical Uplink Shared Channel
- CQI channel quality indicator
- PUCCH Physical Uplink Control Channel
- a CQI report has one of 16 values (numbered from 0 to 15) as specified in TS 36.213 v9.3.0 (see Table 7.2.3-1 ).
- a CQI report reports an indication of the Signal to Interference and Noise conditions as determined by the terminal.
- An eNodeB, receiving CQI reports is enabled to select a corresponding modulation and coding scheme (MCS) for the unicast transmission to the user device. This concept may also be applied for reporting the channel quality and selecting the MCS for the multicast transmission. It is well-known in the art how an MCS can be selected on the basis of a channel quality or on the basis of a CQI report; e.g. see the paper by Alexiou et al., quoted in the background section.
- the modulation and coding scheme for multicast transmission of data in the present disclosure is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter.
- a group of user devices is defined containing more than two members (for example on the basis of the capability and/or enablement of direct wireless communication and/or on the basis of a common interest in a particular multicast)
- a modulation and coding scheme is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter reported by any of the members of the group.
- Multicast transmission of the data over the wireless radio interface is performed in accordance with the selected modulation and coding scheme.
- a system in a telecommunications net- work for multicasting data for at least a first user device and a second user device over a wireless radio interface.
- the system is configured for performing one or more of the steps disclosed in the previous paragraphs.
- the system may be (a portion of) a node in the telecommunications network or may be a separate node or be distributed over several nodes.
- the system is contained in a node, e.g. a base station providing the wireless radio interface, e.g. in an eNodeB.
- the system is contained in a node in the core network, e.g.
- a control node such as an MBMS control node (e.g. the multi-cell coordination entity MCE and/or the mobility management entity MME).
- the system may comprise circuitry programmed with software that, when run by the circuitry, performs the one or more steps of the method.
- a computer program or (non-transitory) computer program product is presented.
- a device for use that is configured for reporting, to the telecommunications network, direct connection information relating to user devices being capable to es- tablish a wireless direct connection with the device.
- an uplink channel associated with a downlink MBMS channel is disclosed.
- the disclosed aspects enable multicasting data to user devices in a manner saving transmission resources, e.g. use a smaller bandwidth to multicast data at a particular bit rate and to, thus, achieve a higher spectral efficiency.
- the modulation and coding scheme in accordance with the best channel quality (e.g. in accordance with the highest value of a channel quality parameter received from a user device) in a group of user devices enabled to establish direct wireless communication amongst members in the group, the transmission of the data from the telecommunications network uses a minimum amount of transmission resources.
- PRBs physical resource blocks
- data can be transmitted at a higher bit rate using the same number of PRBs
- PRBs physical resource blocks
- the modulation and coding rate is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter, (assuming a particular BLER as a parameter), such that transmission resources are used efficiently.
- the telecom munica- tions network applies the higher modulation (more bits per symbol transmitted) and/or coding rate (less redundancy) for the multicast transmission, it is likely that not all user devices may be able to correctly receive all the data (e.g. data packets or data segments) from the multicast transmission.
- the data e.g. data packets or data segments
- the data can be forwarded over the direct connection(s) from a user device possessing a correctly received data packet to a user device not possessing a correctly received data packet.
- the disclosed method and system enable delivery of data (e.g. data packets or data segments) by multicast to several user devices in a manner making efficient use of radio transmission resources by selecting, for the multicast transmission of the data on the wireless radio interface, a modulation and coding scheme in accordance with the best channel quality (e.g. the highest value of a channel quality parameter received from the user devices).
- data e.g. data packets or data segments
- a modulation and coding scheme in accordance with the best channel quality (e.g. the highest value of a channel quality parameter received from the user devices).
- the direct wireless connection may both refer to the LTE proposed device-to-device communication and to other forms of wireless communication not necessarily involving the telecommunications network, such as wireless communication over wifi.
- channel quality information may be expressed in different ways, e.g. in different modalities and/or in different units from e.g. different user devices. Channel quality information expressed in different ways may nevertheless be assessed (e.g. by conversion into a common unit or modality), to determine the best channel quality.
- the telecommunications network may be assisted by other means than the channel quality information obtained from the user devices when assessing channel quality.
- One example includes cell parameter information, such as the transmit power of a cell that can be compared to the RSRP to estimate path loss.
- Another example includes the use of previously received channel quality information, enabling averaging and/or or extrapolation of channel qualities.
- the method and system relate to an LTE telecom- munications network wherein an MBMS multicast is performed.
- Other (next) generation wireless access telecommunications networks may also be used.
- a leader in charge is then defined as the user device having received most data packets correctly.
- the LiC is the user device that, therefore, does most of the retransmissions using D2D links.
- the intuition is that since the LiC receives most of the data packets correctly it can retransmit most of the missing packets for all the non-leaders.
- an intra- cluster rescheduling algorithm is described to reschedule the retransmissions among the user devices in the cluster. It is not described in the article that the modulation and coding rate scheme is selected in accordance with the best channel quality on the wireless radio interface as determined from channel quality information received from a user device.
- the channel quality information may comprise any quantitative information that is indicative of the quality of the radio channel between the telecommunications network (e.g. a base station) and the user device or from which quantitative information of the channel quality can be derived.
- the channel quality information received from the first user device and the second user device at least comprises a value, e.g. a value indicative of a Signal-to- Interference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel and assessing the wireless channel quality on the basis of the value for the first user device and the second user device.
- SINR Signal-to- Interference plus Noise Ratio
- RSRP Reference Signal Received Power
- RSRQ Reference Signal Received Quality
- the method and system are configured for receiving direct connection information from user devices being capable to establish a wireless direct connection with at least one user device.
- the direct connection information may comprise information indicative of the feasibility and/or the quality (e.g. the achievable bit rate) of a direct wireless connection between the user device and another user device, e.g. between the first user device and the second user device and/or e.g. an indication of resources needed (e.g. spectrum bandwidth and/or power) of a direct wireless connection between the user device and another user device to support a specified data rate (e.g. bit rate).
- the user devices capable to establish a wireless direct connection with at least one user device are registered as members of a group of user devices, the group of user devices comprising at least the first user device and the second user device as members of the group of user devices.
- Channel quality information is received from the user devices registered as members of the group of user devices and, from the received channel quality information it is determined that the wireless channel quality for the first user device exceeds the wireless channel quality for the remaining members of the group of user devices, the remaining members including the second user device.
- the modulation and coding scheme is selected in accordance with the wireless channel quality for the first user device and multicast transmission of the data is performed over the wireless radio interface in accordance with the selected modulation and coding scheme.
- the embodiment assists in defining the group of devices for which the channel quality information is assessed to establish the best wireless channel quality to which the modulation and coding rate is to be set or adapted.
- the group may be defined by a shared interest in a particular multicast.
- indications are obtained from at least the first user device and the second user device indicating interest in obtaining the data via multicast.
- the first user device and the second user device are registered as members of a group of user devices in accordance with the obtained indications.
- registered members of the group of devices may be requested from the telecommunications network to report at least one of channel quality information and direct connection information with respect to one or more members of the group of devices. Accordingly, the telecommunications network may obtain up to date information to assess the most efficient manner of multicasting the data.
- the request from the telecommunications network for the information may e.g. be made shortly in advance of the multicast transmission of the data.
- the request may also be repeated, e.g. periodically and/or made dependent on the information received earlier.
- the method and system are configured for transmitting the request including information indicating registered members of the group of devices and receiving direct connection information from the user devices with respect to particular or with respect to only other user devices being registered members of the group of devices. From the information indicating registered members
- the user devices are informed of the user devices for which direct connection information is most relevant for the telecommunications network.
- the method and system are configured for repeatedly, e.g. periodically, receiving, at least one of channel quality information from the first user device and the second user device and direct connection information from the first user device and the second user device, optionally in response to one or more corresponding requests from the telecommunications network to report the information.
- FIG. 1 is a schematic illustration of an eMBMS network
- Fig. 2 is a schematic illustration of an eMBMS telecommunications network according to an embodiment of the invention
- Figs 3A and 3B depict a time diagram and a flow chart illustrating a method according to a first disclosed embodiment
- Figs. 4A and 4B depict a time diagram and a flow chart illustrating a method according to a second disclosed embodiment
- Fig. 5 is a schematic block diagram of a general system or element of a telecommunications network or a user device. DETAILED DESCRIPTION OF THE DRAWINGS
- Fig. 1 is a schematic illustration of a some components of a telecommunications network 1 connected to a further network 2 comprising a content server 3.
- the telecommunications network 1 comprises an LTE or 4G telecommunications network suitable for providing enhanced Multimedia Broadcast Multicast Services eMBMS.
- the content stored in a content server system 3, is provided via a Broadcast Multicast
- BM-SC Service Center
- MBMS gateway MBMS gateway
- eNodeBs base stations
- eNodeBs base stations
- eNodeBs base stations
- Fig. 1 wireless radio interface
- the BM-SC is, amongst others, responsible for service announcement, security and content synchronization.
- the MBMS GW distributes user data to the eNodeBs of the E-UTRAN and performs session control signalling towards the
- MCE Mobility Management Entity
- MCS modulation and coding scheme
- the MCE may be a separate entity of the telecommunications network 1 or be part of the eNodeB(s) in the E-UTRAN. Further information on eMBMS can be found in 3GPP TS 36.300, v.1 1.7.0.
- the MBMS transmission from the different eNodeBs in the E-UTRAN should be received by all user devices 4A-4D interested in and capable of MBMS reception.
- devices may be located at a cell edge where the path loss between the serving cell / eNodeB and a terminal is highest and/or where the interference from surrounding (non-serving) cells / eNodeBs is highest.
- MMSFN MBMS single frequency network
- the multiple eNodeBs are synchronously transmitting the MBMS data towards the user devices 4A-4D such that at the user devices 4A-4D, the transmissions arriving from different cells are received as multipath components of the same signal and not causing interference.
- the MCE function in the telecommunications network needs to properly select a modulation and coding scheme to be applied for the MBMS transmission.
- Different user devices 4A-4D will generally perceive different link qualities (channel qualities) for the wireless radio interface.
- the link quality is influenced by many factors, including noise, interference and path loss.
- the capability of the user device itself may also influence the perceived link quality, dependent e.g. on the receiver quality and/or the quality of device features such as interference cancellation features.
- the transfer rate for the user devices capable of and subscribed to / registered for reception of the multicast can only be as high as that rate that corresponds to the poorest link quality. For example, if streaming video is sent with a certain data rate, a user device with a link quality that is poorer than the quality that corresponds with this data rate may be not able to capture all the streaming video data.
- a user device for a unicast type of transmission, a user device (e.g. one of user devices 4A-4D) periodically reports to the eNodeB the channel quality indicator (CQI) or indirectly the signal-to-interference-and-noise ratio (SINR) experienced in the telecommunications network.
- CQI channel quality indicator
- SINR signal-to-interference-and-noise ratio
- the selected MCS of the physical layer transmission is configured by the MCE to the SINR that the transmission is targeted at, also in combination with the data rate for the MBMS service and with the amount of time-frequency physical resources reserved for the MBMS transmission.
- User devices that experience a lower SINR than the target value used for the configuration may be una- ble to capture all the data of the MBMS service.
- Fig. 2 depicts a schematical illustration of an LTE telecommunications network 1 configured for providing eMBMS services according to an embodiment of the disclosure.
- LTE telecommunications network 1 configured for providing eMBMS services according to an embodiment of the disclosure.
- the disclosed method and system are equally applicable to other manners of multicasting data, e.g. for 3G MBMS ser- vices.
- Fig. 2 it is assumed that the disclosed functionality is implemented in the telecommunications network 1 , particularly in the MCE, schematically illustrated as block 20.
- the MCE and/or the functionality described for block 20 may also be provided in other network nodes, e.g. in one or more eNodeBs.
- the user devices 4A-4D may also have additional functionality implemented for participating in the disclosed method, schematically illustrated by block 21. Details of blocks 20 and 21 are further described with reference to Figs. 3-5.
- D2D Device-to-device
- 3GPP Release 12 The discovery of other D2D-capable user devices and the D2D communication between the user devices are the two basic issues considered in D2D standardization.
- user devices like user devices 4A-4D, are enabled to discover other user devices for D2D communication.
- D2D discovery enables using the LTE wireless radio interface (air interface) to identify other user devices that are in proximity.
- the proximity notion is not only in terms of physical distance, but also based on channel conditions between user devices, signal to interference and noise ratio, throughput, delay, load, etc.
- user devices 4A-4D may be ena- bled to establish other direct wireless connections or links, e.g. out-of-band links, e.g. using a wifi network.
- the method is based on the ability of two or more user devices 4A-4D to establish a direct connection from one user device (e.g. user device 4A) to another user device (e.g. user device 4C) for communicating data, where the data may be received as a multicast over the wireless interface of the telecommunications network 1.
- the telecommunications network 1 acquires the group of user devices that form one MBMS reception group G and their direct connection information, e.g. the D2D communication capabilities.
- user devices 4A, 4C, 4D constitute a group G of user devices enabled at a particular moment in time to establish direct connections (links).
- the telecommunications network 1 e.g.
- the MCE collects periodically information about the channel quality between the serving cell / eNodeB and the user device, as well as about the feasible direct connections (e.g. D2D links) between the user devices.
- the decision logic at the telecommunications network side e.g. located in the MCE
- triggers a multicast transmission based on the best channel quality e.g. based on the highest value of a channel quality parameter which is the direct connection-assisted multicast transmission presented in this disclosure.
- Figs. 3A-3B illustrate a first embodiment of a method applying the system of Fig. 2.
- functional block 20 in the telecommunications network 1 receives channel quality information from each of the user devices 4A, 4C and 4D of the group G of user devices.
- the group G of user devices may, as an option, have been established (shortly) in advance of performing the disclosed method in any manner, e.g. by analyzing direct connection information (not shown) from user devices 4A-4D from which information it is concluded that devices 4A, 4B and 4D can be considered as members of group G.
- the direct connection information is transmitted from the user devices 4A-4D applying functional block 21.
- the group G may be a dynamic group, i.e. the members of the group may vary over time. This may be dependent on e.g. the mobility of the user devices 4A-4D, the radio conditions, the (re- Configuration of user devices, etc.
- Semi-permanent groups may also be considered, e.g. for stationary user devices.
- the channel quality information is indicative of a quality of a wireless channel (e.g. a radio channel) between the telecommunications network 1 and any of the user devices 4A-4D.
- the channel quality information may comprise any quantitative information that is indicative of the quality of the wireless channel or from which quantitative information of quality of the wireless channel for a user device can be derived.
- the user devices 4A-4D may periodically report the channel quality information to the telecommunications network 1.
- the channel quality information received from the user devices at least comprises a value indicative of a Signal-to-lnterference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel.
- SINR Signal-to-lnterference plus Noise Ratio
- RSRP Reference Signal Received Power
- RSRQ Reference Signal Received Quality
- the channel quality information comprises CQI reports as known for unicast transmission, wherein the CQI is based on the estimated SINR.
- the CQI may be based on any, or any combination, of the SINR, RSRP, RSRQ or path loss estimate.
- step S32 functional block 20 in the telecommunications network assesses the received channel quality information and derives a measure of the channel qualities from the information for each of the user devices 4A, 4C and 4D.
- the modulation and coding scheme for multicast transmission of data in the present disclosure is selected in accordance with the best channel quality for the group G of user devices.
- the MCS is selected in accordance with the best channel quality amongst the members of the group G.
- functional block 20 in the telecommunications network 1 may find that the channel quality is best for user device 4D and select, set or adapt the MCS in accordance with the channel quality derived for user device 4D.
- user devices may report equal channel quality information and/or that channel qualities may be derived as equal. If this channel quality is the best channel quality, the MCS is selected in accordance with this channel quality and the MCS is optimal for a plurality of user devices.
- the telecommunications network performs multicast transmission of the data in accordance with the selected MCS, i.e. in accordance with the MCS selected in accordance with the channel quality determined from the channel quality information reported by user device 4D.
- the thick arrows in Fig. 3A This is indicated by the thick arrows in Fig. 3A.
- the lighter greyscale of the arrows indicates a greater likelihood that user devices 4A and 4C, for which a poorer channel quality was determined than for user device 4D, do not appropriately receive all the multicast data since the MCS is not selected in accordance with their channel qualities reported in or derived from the channel quality information received from these user devices 4A, 4C.
- the user devices 4A, 4C, 4D transmit data parts (e.g. data packets or data segments) that have not been correctly received by one or more user devices in the group G from the telecommunications network's multicast transmission for the group G.
- D2D direct links e.g. a D2D direct link between 4D and 4C, one between 4D and 4A and one between 4C and 4A
- enable cooperation between the user devices 4A, 4C and 4D to resolve parts of the data (e.g. data packets or data segments) that have not been obtained directly from the multicast transmission of telecommunications network 1.
- user device 4A receives lacking data from user devices 4C and 4D and user device 4C receives lacking data from user device 4D.
- Other group-internal transmission configurations are also possible.
- telecommunications network and the data exchange arrows between the user devices indicates that the timing of the telecommunications network multicast transmission followed by the transmissions between the group members is not necessarily in the order drawn in Fig. 3A.
- user device 4C may start transmitting copies of a data part to other user devices in group G as soon as user device 4C has received the data part (either from the telecommunications network's multicast transmission or from a direct connection).
- the dashed box thus also indicates that multicasting the data from the telecommunications network 1 is not necessarily completed before a user device transmits a received data part on a direct connection.
- user device 4D transmits data as a multicast for two or more user devices within the group G.
- the invention may, mutatis mutandis, also be applied to such multicast transmission from a user device.
- Figs. 4A and 4B disclose another embodiment of the multicast method.
- user devices 4A-4D are informed (e.g. via a conventional multicast, e.g. a cell broadcast, via separate unicast connections or via a combination) of user devices that are considered as members of a group that is interested in the multicast.
- the network signal includes information that user devices 4A, 4C and 4D are interested in the multicast.
- Functional component 21 in each of these user devices then considers the direct connection information for in particular or for only the members.
- step S42 the relevant direct connection information is transmitted from each of the user devices 4A, 4C and 4D to the telecommunications network 1 , in particular to the node comprising functional block 20, e.g. the MCE.
- the direct connection information may comprise the feasibility of and/or the quality of the direct connections between the user devices identified as a group in step S41.
- step S41 is omitted and the user devices 4A-4D each report direct connection information for all devices for which this information is available.
- step S42 channel quality information with respect to the wireless radio interface of the telecommunications network 1 is transmitted by each of the user devices 4A-4D using functional component 21 as in the embodiment of Figs. 3A and 3B.
- the direct connection information is transmitted along with the channel quality information, this is not necessary.
- the information may be transmitted using different signals and the frequency of transmission may also be different.
- the direct connection information may be transmitted less frequently than the channel quality information.
- the performance of the method will, however, improve if the telecommunications network 1 has up-to-date information on both the channel qualities and the direct connection qualities.
- Functional block 20 in the telecommunications network 1 receives the information from each of the user devices 4A, 4C and 4D.
- the channel quality information comprises CQI reports as known for unicast transmission, wherein the CQI is based on the estimated SINR.
- the CQI may be based on any, or any combination, of the SINR, RSRP, RSRQ or path loss estimate.
- step S43 functional block 20 in the telecommunications network assesses the received channel quality information and the direct connection information received from the user devices.
- functional block 21 deter- mines that user devices 4A, 4C and 4D have a direct connection feasibility and/or have a direct connection quality that is sufficient to form a group G for which the MCS can be set in accordance with the best channel quality of the wireless radio interface for these user devices 4A, 4C and 4D.
- the channel quality is best for user device 4D (e.g. SINR reported by or derived for user device 4D exceeds SINR reported by or de- rived for user devices 4A and 4C)
- the MCS is set in accordance with the channel quality (e.g. the SINR) for user device 4D.
- the telecommunications network 1 performs multicast transmission of the data in accordance with the selected MCS, i.e. in accordance with the MCS selected in accordance with the channel quality determined from the channel quality information reported by user device 4D.
- the thick arrows in Fig. 4A This is indicated by the thick arrows in Fig. 4A.
- the lighter greyscale of the arrows indicates a greater likelihood that user devices 4A and 4C, for which a poorer channel quality was determined than for user device 4D, do not appropriately receive all the multicast data since the MCS is not selected in accordance with their channel quality.
- the user device 4D transmits data parts (e.g. data packets or data segments) that has not been correctly received by user devices 4A, 4C from the telecommunication network's multicast transmission.
- the user device 4D transmits the data parts over the direct wireless connections, e.g. over D2D links.
- Functional block 20 in the telecommunications network may decide when to switch from the prior art multicast method of selecting the MCS in accordance with a target SINR (which could be considered to correspond to a target channel quality) to the multicast method of selecting the MCS in accordance with the best channel quality as determined or derived from channel quality information received from a group of devices capable of distributing the multicast data over direct wireless connections within the group.
- a signal containing an indication of the application of the latter method is transmitted to the user devices.
- Functional block 21 in the user devices transmits at least one of channel quality information and direct connection information to the telecommunications network 1 in response to receiving the (instruction) signal containing the indication from the telecommunications network 1 .
- Fig. 5 is a block diagram illustrating an exemplary data processing system 50 that may be used as a device 4A-4D comprising functional block 21 or as a network node containing functional block 20, e.g. an MCE, in the telecommunications network 1.
- a device 4A-4D comprising functional block 21 or as a network node containing functional block 20, e.g. an MCE, in the telecommunications network 1.
- Data processing system 50 may include at least one processor 51 coupled to memory elements 52 through a system bus 53. As such, the data processing system 50 may store program code within memory elements 52. Further, processor 51 may execute the program code accessed from memory elements 52 via system bus 53. In one aspect, data processing system 50 may be implemented as a computer that is suitable for storing and/or executing program code. It should be appreciated, however, that data processing system 50 may be implemented in the form of any system including a processor and memory that is capable of performing the functions described within this disclosure.
- Memory elements 52 may include one or more physical memory devices such as, for ex- ample, local memory 54 and one or more bulk storage devices 55.
- Local memory 54 may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code.
- a bulk storage device may be implemented as a hard drive or other persistent data storage device.
- the data processing system 50 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the number of times program code must be retrieved from bulk storage device 55 during execution.
- I/O devices depicted as input device 56 and output device 57 optionally can be coupled to the data processing system 50.
- input devices may include, but are not limited to, for example, a keyboard, a pointing device such as a mouse, a touchscreen, or the like.
- output device may include, but are not limited to, for example, a monitor or display, speakers, or the like.
- Input device 56 and/or output device 57 may be coupled to data processing system 50 either directly or through intervening I/O controllers.
- a network adapter 58 may also be coupled to data processing system 50 to enable it to become coupled to other systems, computer systems, remote network devices, and/or remote storage devices through intervening private or public networks.
- the network adapter 58 may comprise a data receiver for receiving data that is transmitted by said systems, devices and/or networks to said data processing system 50 and a data transmitter for transmitting data to said systems, devices and/or networks.
- Modems, cable modems, and Ethernet cards are examples of different types of network adapters that may be used with data processing system 50.
- memory elements 52 may store an application 59. It should be ap- preciated that data processing system 50 may further execute an operating system (not shown) that can facilitate execution of the application. Applications, being implemented in the form of executable program code, can be executed by data processing system 50, e.g., by processor 51. Responsive to executing the application 59, the data processing system 50 may be configured to perform one or more operations to be described herein in further detail.
- data processing system 50 may represent a client data processing system, e.g. within user devices 4A-4D.
- application 59 may represent a client application that, when executed, configures data processing system 50 to perform the various functions described herein for the device containing functional block 21.
- client can include, but are not limited to, a personal computer, a portable computer, a mobile phone, or the like.
- data processing system 50 may represent a network node containing functional block 20, e.g. an MCE or a base station in which case application 59, when executed, may configure data processing system 50 to perform operations as described in the present disclosure.
- application 59 when executed, may configure data processing system 50 to perform operations as described in the present disclosure.
- Various embodiments of the invention may be implemented as a program product for use with a computer system or a processor, where the program(s) of the program product define functions of the embodiments (including the methods described herein).
- the program(s) can be contained on a variety of non-transitory computer-readable storage media (generally referred to as "storage"), where, as used herein, the expression “non-transitory computer readable storage media” comprises all computer-readable media, with the sole exception being a transitory, propagating signal.
- the program(s) can be contained on a variety of transitory computer-readable storage media.
- Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored.
- non-writable storage media e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory
- writable storage media e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory
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Abstract
The disclosure relates to an efficient multicasting method and system applying direct wireless connections between user devices. The telecommunications network is enabled to select the optimal modulation and coding scheme for a group of user devices enabled to transmit multicast data over the direct wireless connection in accordance with the best channel quality reported by a user device.
Description
Efficient multicasting method and system applying direct device-to-device connections
FIELD OF THE INVENTION
The invention relates to a method and system for providing data to a plurality of user devices. More specifically, the invention relates to an efficient method and system for multicasting data to a group of devices being enabled to establish device-to-device connections.
BACKGROUND
Multicasting in a traditional and commonly known form pertains to a method for delivering data comprising one or more data packets to a group of user devices simultaneously in a single transmission from a source. If a network is involved, copies of the data packets are created in network elements, such as routers, when required by the topology of the network. In e.g. IP multicast, which is often employed in Internet Protocol (IP) applications for streaming media and Internet television, the multicast (copying of IP packets) occurs at the IP routing level, where multicast-enabled IP routers copy and forward, as far as needed, IP data packets addressed to a multicast destination address.
From the 3GPP standard for mobile communication systems a Multimedia Broad- cast/Multicast Service (MBMS) is known which is designed to deliver broadcast and multicast services from a single base station or group of base stations to multiple user devices receiving the same content. The primary benefit of MBMS is more efficient utilization of network and frequency spectrum resources by ensuring that content to be delivered to several user devices uses, on the path from the source via one or more base stations to user devices, a single channel or bit stream rather than individual bit streams to each user device. In the multicast mode of MBMS, a user of a user device (terminal, UE) can separately order one or more of the multicast services available in the cell serving the user device. The subscription and group joining for the multicast mode services could be done by the mobile network operator, the user or a separate service provider.
Recent developments in the 3GPP standard relate to Long Term Evolution (LTE) and Long Term Evolution Advanced (LTE Advanced) telecommunications networks and devices. LTE and
LTE Advanced, also known as the 4G (i.e. fourth generation) mobile communications standard, is a standard for wireless communication of high-speed data for mobile user devices (terminals) such as smartphones, (tablet) computers or other (data) devices. It is a successor of GSM/EDGE (also known as 2G or 2.5G) and UMTS/HSPA (also known as 3G) telecommunications network technologies, increasing the capacity and speed using, compared to previous technologies, a different radio interface together with improvements and enhancements in the access and core network.
The paper Modulation and coding scheme selection in multimedia broadcast of a single frequency network-enabled long-term evolution network by A. Alexiou et al., published in Int. J. Commun. Syst. (201 1 ) discloses methods in LTE systems to improve spectral efficiency by selecting modulation and coding scheme (MCS). The modulation and coding scheme is expressed as an index in a predefined
list of several combinations of modulation and coding that may be used in the multicast transmission from a base station to the user devices. The applied modulation determines the number of bits that is carried in one transmitted symbol (examples of modulation include QPSK, 16QAM en 64QAM). In order to provide some protection against propagation errors on the wireless path, redundancy is added to the data bits to be transmitted, thus increasing the total number of bits to be transmitted. A higher channel quality allows a higher order modulation to be applied, e.g. 16QAM instead of QPSK (with a certain bit error ratio as a parameter). The applied coding rate determines the ratio (smaller than one, examples include 4/5, 1/2, 1/3) of the number of data bits to be transmitted over the total number of bits to be transmitted. A higher channel quality also allows less redundancy to be applied, e.g. 4/5 or 1/2 instead of 1/3 (with a certain block error ratio as a parameter). An ordered list of channel qualities may be mapped onto a correspondingly ordered list of combinations of a particular modulation and a particular coding rate (with a certain block error ratio as a parameter).
In the paper of Alexiou et al., the spectral efficiency for transmission to a single user device is determined by the data rate at which data can be successfully transmitted over a given bandwidth of the wireless radio interface. For multicast transmission to several user devices, the spectral efficiency is determined by the data rate averaged over the user devices. In the paper, it is described that the spectral efficiency is directly related to the MCS selected for the transmission and that the MCS is selected from a pre-defined list of modulation and coding schemes based on signal-to-interference plus noise ratio (SINR) values as measured by the terminals. In this SINR-to-MCS mapping a certain expected maximum or target block error rate (BLER, e.g. 10%) is used as a parameter. Four approaches are described for selecting the MCS, ranging from an approach wherein all user devices in an area receive an MBMS service, at the cost of a low spectrum efficiency, to approaches wherein not all user devices receive an MBMS service but a maximum spectrum efficiency is ensured or a predefined minimum or threshold or target for the spectrum efficiency is achieved.
In practice, it is highly undesirable that certain user devices cannot properly receive the multicast data. Yet, in view of the inherent scarcity of radio transmission resources, operators of wireless access telecommunications network need to control the resources allocated to transmissions over the wireless radio interface, including multicast transmissions. Therefore, there is a need in the art to improve data transmission over the radio interface, in particular for multicast transmissions.
SUMMARY
As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, a software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," "module" or "system". Functions described in this disclosure may be implemented as an algorithm executed by a microprocessor of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in
one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.
Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a solid-state drive, a random access memory (RAM), a non-volatile memory device, a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this disclosure, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless (using electromagnetic and/or optical radiation), wired, optical fiber, cable, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java(TM), Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on a user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
Aspects of the present invention are described below with reference to flowchart illustra- tions and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor, in particular a microprocessor or central processing unit (CPU), of a general purpose
computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the functions noted in the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In one aspect, the present disclosure presents a method for multicasting data for at least a first user device and a second user device from a telecommunications network over a wireless radio interface. The first user device and the second user device are enabled to establish a connection with the telecommunications network over the wireless radio interface and to establish a direct wireless connection with each other. The registration of the capability and/or enablement for establishing direct connections may be a step in the disclosed method.
The method comprises a step in the telecommunications system of receiving channel quality information from the first user device and the second user device, the channel quality information being indicative of a wireless channel quality of a wireless channel between the telecommunications network and the first user device and the second user device, respectively. The channel quality information may comprise any, e.g. quantitative, information that is indicative of the quality of the radio channel or from which quantitative information of the radio channel quality to a user device can be derived. The
channel quality information may be an estimate, an approximation or a representation of the actual channel quality. The channel quality information enables, possibly by derivation, to distinguish between poorer and better channel qualities experienced by the user devices.
From the received channel quality information, it can be determined for which user device the experienced channel quality is best (e.g. by analysing the (absolute) value of a channel quality parameter). The user devices may report the channel quality information to the telecommunications network, e.g. periodically and/or in response to a request received from the network, using e.g. CQI report. In LTE telecommunications networks for a unicast transmission from the telecommunications network to a user device, the user device periodically reports the channel quality indicator (CQI) to the eNodeB via the Physical Uplink Control Channel (PUCCH) or, if Physical Uplink Shared Channel
(PUSCH) is available, the eNodeB might request the CQI report on demand as specified in TS 36.213 v9.3.0 ('Physical Layer Procedures (Release 9)'). A CQI report has one of 16 values (numbered from 0 to 15) as specified in TS 36.213 v9.3.0 (see Table 7.2.3-1 ). A CQI report reports an indication of the Signal to Interference and Noise conditions as determined by the terminal. An eNodeB, receiving CQI reports, is enabled to select a corresponding modulation and coding scheme (MCS) for the unicast transmission to the user device. This concept may also be applied for reporting the channel quality and selecting the MCS for the multicast transmission. It is well-known in the art how an MCS can be selected on the basis of a channel quality or on the basis of a CQI report; e.g. see the paper by Alexiou et al., quoted in the background section.
In contrast to selecting the modulation and coding scheme in accordance with prior art mechanisms, the modulation and coding scheme for multicast transmission of data in the present disclosure is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter. If a group of user devices is defined containing more than two members (for example on the basis of the capability and/or enablement of direct wireless communication and/or on the basis of a common interest in a particular multicast), a modulation and coding scheme is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter reported by any of the members of the group. Multicast transmission of the data over the wireless radio interface is performed in accordance with the selected modulation and coding scheme.
In another aspect of the disclosure, a system is presented in a telecommunications net- work for multicasting data for at least a first user device and a second user device over a wireless radio interface. The system is configured for performing one or more of the steps disclosed in the previous paragraphs. The system may be (a portion of) a node in the telecommunications network or may be a separate node or be distributed over several nodes. In one embodiment, the system is contained in a node, e.g. a base station providing the wireless radio interface, e.g. in an eNodeB. In another embodi- ment, the system is contained in a node in the core network, e.g. in a control node, such as an MBMS control node (e.g. the multi-cell coordination entity MCE and/or the mobility management entity MME). In order to perform the one or more steps of the method, the system may comprise circuitry programmed with software that, when run by the circuitry, performs the one or more steps of the method.
In yet another aspect of the disclosure, a computer program or (non-transitory) computer program product is presented.
In still another aspect, a device is disclosed for use that is configured for reporting, to the telecommunications network, direct connection information relating to user devices being capable to es- tablish a wireless direct connection with the device.
In a yet further aspect, an uplink channel associated with a downlink MBMS channel is disclosed.
The disclosed aspects enable multicasting data to user devices in a manner saving transmission resources, e.g. use a smaller bandwidth to multicast data at a particular bit rate and to, thus, achieve a higher spectral efficiency. By selecting or adapting the modulation and coding scheme in accordance with the best channel quality (e.g. in accordance with the highest value of a channel quality parameter received from a user device) in a group of user devices enabled to establish direct wireless communication amongst members in the group, the transmission of the data from the telecommunications network uses a minimum amount of transmission resources.
Accordingly, fewer physical resource blocks (PRBs) are required for transmission of the data at a particular bit rate (or, alternatively, data can be transmitted at a higher bit rate using the same number of PRBs) when the modulation and coding rate is selected in accordance with the best channel quality, e.g. in accordance with the highest value of a channel quality parameter, (assuming a particular BLER as a parameter), such that transmission resources are used efficiently. When the telecom munica- tions network applies the higher modulation (more bits per symbol transmitted) and/or coding rate (less redundancy) for the multicast transmission, it is likely that not all user devices may be able to correctly receive all the data (e.g. data packets or data segments) from the multicast transmission. However, as a result of the user devices being enabled to establish direct wireless connection(s), the data (e.g. data packets or data segments) can be forwarded over the direct connection(s) from a user device possessing a correctly received data packet to a user device not possessing a correctly received data packet.
In summary, the disclosed method and system enable delivery of data (e.g. data packets or data segments) by multicast to several user devices in a manner making efficient use of radio transmission resources by selecting, for the multicast transmission of the data on the wireless radio interface, a modulation and coding scheme in accordance with the best channel quality (e.g. the highest value of a channel quality parameter received from the user devices).
It should be noted that the direct wireless connection may both refer to the LTE proposed device-to-device communication and to other forms of wireless communication not necessarily involving the telecommunications network, such as wireless communication over wifi.
It is to be understood that channel quality information may be expressed in different ways, e.g. in different modalities and/or in different units from e.g. different user devices. Channel quality information expressed in different ways may nevertheless be assessed (e.g. by conversion into a common unit or modality), to determine the best channel quality.
It should also be understood that the telecommunications network may be assisted by other means than the channel quality information obtained from the user devices when assessing channel
quality. One example includes cell parameter information, such as the transmit power of a cell that can be compared to the RSRP to estimate path loss. Another example includes the use of previously received channel quality information, enabling averaging and/or or extrapolation of channel qualities.
In one embodiment of the disclosure, the method and system relate to an LTE telecom- munications network wherein an MBMS multicast is performed. Other (next) generation wireless access telecommunications networks may also be used.
In the article Reliable Multicasting for Device-to-Device Radio Underlaying Cellular Networks by W. Yang et al, Cornell University Library, a Leader in Charge (LiC) reliable multicast architecture is known for D2D radio underlaying cellular networks. In particular, two kinds of transmis- sions are described: multicast from eNodeB and intra-cluster retransmission. Data packets are first multicast on the cellular links by the eNodeB. Next they are retransmitted in a cluster of user device on D2D links until each of the user devices has correctly received all data packets. The eNodeB does not need to transmit until all user devices have received the data packets correctly, but only until the cluster has received all data packets correctly. A leader in charge (LiC) is then defined as the user device having received most data packets correctly. The LiC is the user device that, therefore, does most of the retransmissions using D2D links. The intuition is that since the LiC receives most of the data packets correctly it can retransmit most of the missing packets for all the non-leaders. Furthermore, an intra- cluster rescheduling algorithm is described to reschedule the retransmissions among the user devices in the cluster. It is not described in the article that the modulation and coding rate scheme is selected in accordance with the best channel quality on the wireless radio interface as determined from channel quality information received from a user device.
As has been mentioned above, the channel quality information may comprise any quantitative information that is indicative of the quality of the radio channel between the telecommunications network (e.g. a base station) and the user device or from which quantitative information of the channel quality can be derived. In one embodiment, the channel quality information received from the first user device and the second user device at least comprises a value, e.g. a value indicative of a Signal-to- Interference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel and assessing the wireless channel quality on the basis of the value for the first user device and the second user device.
In one embodiment, the method and system are configured for receiving direct connection information from user devices being capable to establish a wireless direct connection with at least one user device. The direct connection information may comprise information indicative of the feasibility and/or the quality (e.g. the achievable bit rate) of a direct wireless connection between the user device and another user device, e.g. between the first user device and the second user device and/or e.g. an indication of resources needed (e.g. spectrum bandwidth and/or power) of a direct wireless connection between the user device and another user device to support a specified data rate (e.g. bit rate). The user devices capable to establish a wireless direct connection with at least one user device are registered as members of a group of user devices, the group of user devices comprising at least the first user device
and the second user device as members of the group of user devices. Channel quality information is received from the user devices registered as members of the group of user devices and, from the received channel quality information it is determined that the wireless channel quality for the first user device exceeds the wireless channel quality for the remaining members of the group of user devices, the remaining members including the second user device. The modulation and coding scheme is selected in accordance with the wireless channel quality for the first user device and multicast transmission of the data is performed over the wireless radio interface in accordance with the selected modulation and coding scheme. The embodiment assists in defining the group of devices for which the channel quality information is assessed to establish the best wireless channel quality to which the modulation and coding rate is to be set or adapted.
In addition, or alternatively, the group may be defined by a shared interest in a particular multicast. To that end, indications are obtained from at least the first user device and the second user device indicating interest in obtaining the data via multicast. The first user device and the second user device are registered as members of a group of user devices in accordance with the obtained indications.
If the group of devices has been defined, registered members of the group of devices may be requested from the telecommunications network to report at least one of channel quality information and direct connection information with respect to one or more members of the group of devices. Accordingly, the telecommunications network may obtain up to date information to assess the most efficient manner of multicasting the data. The request from the telecommunications network for the information may e.g. be made shortly in advance of the multicast transmission of the data. The request may also be repeated, e.g. periodically and/or made dependent on the information received earlier.
In one embodiment, the method and system are configured for transmitting the request including information indicating registered members of the group of devices and receiving direct connection information from the user devices with respect to particular or with respect to only other user devices being registered members of the group of devices. From the information indicating registered members
(e.g. a list of device identifiers), the user devices are informed of the user devices for which direct connection information is most relevant for the telecommunications network.
In one embodiment, the method and system are configured for repeatedly, e.g. periodically, receiving, at least one of channel quality information from the first user device and the second user device and direct connection information from the first user device and the second user device, optionally in response to one or more corresponding requests from the telecommunications network to report the information.
It is noted that the invention relates to all possible combinations of features recited in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the invention will be explained in greater detail by reference to exemplary embodiments shown in the drawings, in which:
Fig. 1 is a schematic illustration of an eMBMS network;
Fig. 2 is a schematic illustration of an eMBMS telecommunications network according to an embodiment of the invention;
Figs 3A and 3B depict a time diagram and a flow chart illustrating a method according to a first disclosed embodiment;
Figs. 4A and 4B depict a time diagram and a flow chart illustrating a method according to a second disclosed embodiment; and
Fig. 5 is a schematic block diagram of a general system or element of a telecommunications network or a user device. DETAILED DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic illustration of a some components of a telecommunications network 1 connected to a further network 2 comprising a content server 3. The telecommunications network 1 comprises an LTE or 4G telecommunications network suitable for providing enhanced Multimedia Broadcast Multicast Services eMBMS.
The content, stored in a content server system 3, is provided via a Broadcast Multicast
Service Center (BM-SC) and an MBMS gateway (MBMS GW) towards base stations (eNodeBs, comprised in the E-UTRAN and not separately shown in Fig. 1 ) over a wireless radio interface provided by the E-UTRAN to user devices 4A-4D as a multicast (indicated by the black arrow). The BM-SC is, amongst others, responsible for service announcement, security and content synchronization. The MBMS GW distributes user data to the eNodeBs of the E-UTRAN and performs session control signalling towards the
E-UTRAN via the Mobility Management Entity (MME). A Multi-cell/multicast Coordination Entity (MCE) controls the allocation of radio resources (time, frequency) and the selection of an appropriate modulation and coding scheme (MCS). The MCE may be a separate entity of the telecommunications network 1 or be part of the eNodeB(s) in the E-UTRAN. Further information on eMBMS can be found in 3GPP TS 36.300, v.1 1.7.0.
The MBMS transmission from the different eNodeBs in the E-UTRAN should be received by all user devices 4A-4D interested in and capable of MBMS reception. In the worst case, devices may be located at a cell edge where the path loss between the serving cell / eNodeB and a terminal is highest and/or where the interference from surrounding (non-serving) cells / eNodeBs is highest. In order to pro- vide for robust MBMS transmission for the cell edge terminals, the concept of MBMS single frequency network (MBSFN) has been introduced. Within the MBSFN area the multiple eNodeBs are synchronously transmitting the MBMS data towards the user devices 4A-4D such that at the user devices 4A-4D, the transmissions arriving from different cells are received as multipath components of the same signal and not causing interference.
For appropriate MBMS reception, the MCE function in the telecommunications network needs to properly select a modulation and coding scheme to be applied for the MBMS transmission. Different user devices 4A-4D will generally perceive different link qualities (channel qualities) for the wireless radio interface. The link quality is influenced by many factors, including noise, interference and path
loss. The capability of the user device itself may also influence the perceived link quality, dependent e.g. on the receiver quality and/or the quality of device features such as interference cancellation features.
The transfer rate for the user devices capable of and subscribed to / registered for reception of the multicast can only be as high as that rate that corresponds to the poorest link quality. For example, if streaming video is sent with a certain data rate, a user device with a link quality that is poorer than the quality that corresponds with this data rate may be not able to capture all the streaming video data.
In LTE telecommunications networks, for a unicast type of transmission, a user device (e.g. one of user devices 4A-4D) periodically reports to the eNodeB the channel quality indicator (CQI) or indirectly the signal-to-interference-and-noise ratio (SINR) experienced in the telecommunications network. For MBMS transmission the selected MCS of the physical layer transmission is configured by the MCE to the SINR that the transmission is targeted at, also in combination with the data rate for the MBMS service and with the amount of time-frequency physical resources reserved for the MBMS transmission. User devices that experience a lower SINR than the target value used for the configuration may be una- ble to capture all the data of the MBMS service.
Fig. 2 depicts a schematical illustration of an LTE telecommunications network 1 configured for providing eMBMS services according to an embodiment of the disclosure. Although the following description focusses on such a telecommunications network, it should be appreciated that the disclosed method and system are equally applicable to other manners of multicasting data, e.g. for 3G MBMS ser- vices.
In the embodiment of Fig. 2, it is assumed that the disclosed functionality is implemented in the telecommunications network 1 , particularly in the MCE, schematically illustrated as block 20. The MCE and/or the functionality described for block 20, may also be provided in other network nodes, e.g. in one or more eNodeBs. The user devices 4A-4D may also have additional functionality implemented for participating in the disclosed method, schematically illustrated by block 21. Details of blocks 20 and 21 are further described with reference to Figs. 3-5.
Device-to-device (D2D) communication will likely be added to LTE in 3GPP Release 12. The discovery of other D2D-capable user devices and the D2D communication between the user devices are the two basic issues considered in D2D standardization. In the present disclosure, it is assumed that user devices, like user devices 4A-4D, are enabled to discover other user devices for D2D communication. D2D discovery enables using the LTE wireless radio interface (air interface) to identify other user devices that are in proximity. The proximity notion is not only in terms of physical distance, but also based on channel conditions between user devices, signal to interference and noise ratio, throughput, delay, load, etc. In addition or as an alternative to D2D communication, user devices 4A-4D may be ena- bled to establish other direct wireless connections or links, e.g. out-of-band links, e.g. using a wifi network.
The method is based on the ability of two or more user devices 4A-4D to establish a direct connection from one user device (e.g. user device 4A) to another user device (e.g. user device 4C) for communicating data, where the data may be received as a multicast over the wireless interface of the
telecommunications network 1. As a first step, the telecommunications network 1 acquires the group of user devices that form one MBMS reception group G and their direct connection information, e.g. the D2D communication capabilities. In Fig. 2, user devices 4A, 4C, 4D constitute a group G of user devices enabled at a particular moment in time to establish direct connections (links). In the second step the telecommunications network 1 (e.g. MCE) collects periodically information about the channel quality between the serving cell / eNodeB and the user device, as well as about the feasible direct connections (e.g. D2D links) between the user devices. Finally, in the third step, based on the information collected in the second step, the decision logic at the telecommunications network side (e.g. located in the MCE) triggers a multicast transmission based on the best channel quality (e.g. based on the highest value of a channel quality parameter) which is the direct connection-assisted multicast transmission presented in this disclosure.
Figs. 3A-3B illustrate a first embodiment of a method applying the system of Fig. 2.
In a first step, S31 , functional block 20 in the telecommunications network 1 receives channel quality information from each of the user devices 4A, 4C and 4D of the group G of user devices. The group G of user devices may, as an option, have been established (shortly) in advance of performing the disclosed method in any manner, e.g. by analyzing direct connection information (not shown) from user devices 4A-4D from which information it is concluded that devices 4A, 4B and 4D can be considered as members of group G. The direct connection information is transmitted from the user devices 4A-4D applying functional block 21. The group G may be a dynamic group, i.e. the members of the group may vary over time. This may be dependent on e.g. the mobility of the user devices 4A-4D, the radio conditions, the (re- Configuration of user devices, etc. Semi-permanent groups may also be considered, e.g. for stationary user devices.
The channel quality information is indicative of a quality of a wireless channel (e.g. a radio channel) between the telecommunications network 1 and any of the user devices 4A-4D. The channel quality information may comprise any quantitative information that is indicative of the quality of the wireless channel or from which quantitative information of quality of the wireless channel for a user device can be derived. The user devices 4A-4D may periodically report the channel quality information to the telecommunications network 1. The channel quality information received from the user devices at least comprises a value indicative of a Signal-to-lnterference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel. In one embodiment, the channel quality information comprises CQI reports as known for unicast transmission, wherein the CQI is based on the estimated SINR. For the present disclosure, the CQI may be based on any, or any combination, of the SINR, RSRP, RSRQ or path loss estimate.
In step S32, functional block 20 in the telecommunications network assesses the received channel quality information and derives a measure of the channel qualities from the information for each of the user devices 4A, 4C and 4D. In contrast to selecting the modulation and coding scheme in accordance with prior art mechanisms, the modulation and coding scheme for multicast transmission of data in the present disclosure is selected in accordance with the best channel quality for the group G of
user devices. Thus, the MCS is selected in accordance with the best channel quality amongst the members of the group G. For example, functional block 20 in the telecommunications network 1 may find that the channel quality is best for user device 4D and select, set or adapt the MCS in accordance with the channel quality derived for user device 4D.
It should be noted that user devices may report equal channel quality information and/or that channel qualities may be derived as equal. If this channel quality is the best channel quality, the MCS is selected in accordance with this channel quality and the MCS is optimal for a plurality of user devices.
In a next step, S33, the telecommunications network performs multicast transmission of the data in accordance with the selected MCS, i.e. in accordance with the MCS selected in accordance with the channel quality determined from the channel quality information reported by user device 4D. This is indicated by the thick arrows in Fig. 3A. The lighter greyscale of the arrows indicates a greater likelihood that user devices 4A and 4C, for which a poorer channel quality was determined than for user device 4D, do not appropriately receive all the multicast data since the MCS is not selected in accordance with their channel qualities reported in or derived from the channel quality information received from these user devices 4A, 4C.
The user devices 4A, 4C, 4D transmit data parts (e.g. data packets or data segments) that have not been correctly received by one or more user devices in the group G from the telecommunications network's multicast transmission for the group G. For example, D2D direct links (e.g. a D2D direct link between 4D and 4C, one between 4D and 4A and one between 4C and 4A) enable cooperation between the user devices 4A, 4C and 4D to resolve parts of the data (e.g. data packets or data segments) that have not been obtained directly from the multicast transmission of telecommunications network 1.
In the case of Fig. 3A, user device 4A receives lacking data from user devices 4C and 4D and user device 4C receives lacking data from user device 4D. Other group-internal transmission configurations are also possible. The dashed box drawn around the multicast arrows from the
telecommunications network and the data exchange arrows between the user devices indicates that the timing of the telecommunications network multicast transmission followed by the transmissions between the group members is not necessarily in the order drawn in Fig. 3A. For example, user device 4C may start transmitting copies of a data part to other user devices in group G as soon as user device 4C has received the data part (either from the telecommunications network's multicast transmission or from a direct connection). The dashed box thus also indicates that multicasting the data from the telecommunications network 1 is not necessarily completed before a user device transmits a received data part on a direct connection. Though currently not planned to be standardised for LTE Advanced, it may also be envisaged that user device 4D transmits data as a multicast for two or more user devices within the group G. The invention may, mutatis mutandis, also be applied to such multicast transmission from a user device.
Figs. 4A and 4B disclose another embodiment of the multicast method.
In step S41 , user devices 4A-4D are informed (e.g. via a conventional multicast, e.g. a cell broadcast, via separate unicast connections or via a combination) of user devices that are considered as members of a group that is interested in the multicast. The network signal, in this embodiment, includes information that user devices 4A, 4C and 4D are interested in the multicast. Functional component 21 in each of these user devices then considers the direct connection information for in particular or for only the members.
In step S42, the relevant direct connection information is transmitted from each of the user devices 4A, 4C and 4D to the telecommunications network 1 , in particular to the node comprising functional block 20, e.g. the MCE. The direct connection information may comprise the feasibility of and/or the quality of the direct connections between the user devices identified as a group in step S41. Alternatively, step S41 is omitted and the user devices 4A-4D each report direct connection information for all devices for which this information is available.
Furthermore, in step S42, channel quality information with respect to the wireless radio interface of the telecommunications network 1 is transmitted by each of the user devices 4A-4D using functional component 21 as in the embodiment of Figs. 3A and 3B. Whereas in the embodiment of Figs. 4A and 4B, the direct connection information is transmitted along with the channel quality information, this is not necessary. The information may be transmitted using different signals and the frequency of transmission may also be different. For example, the direct connection information may be transmitted less frequently than the channel quality information. The performance of the method will, however, improve if the telecommunications network 1 has up-to-date information on both the channel qualities and the direct connection qualities. Functional block 20 in the telecommunications network 1 receives the information from each of the user devices 4A, 4C and 4D.
Again, in one embodiment, the channel quality information comprises CQI reports as known for unicast transmission, wherein the CQI is based on the estimated SINR. For the present disclo- sure, the CQI may be based on any, or any combination, of the SINR, RSRP, RSRQ or path loss estimate.
In step S43, functional block 20 in the telecommunications network assesses the received channel quality information and the direct connection information received from the user devices. From the direct connection information, in the embodiment of Figs. 4A and 4B, functional block 21 deter- mines that user devices 4A, 4C and 4D have a direct connection feasibility and/or have a direct connection quality that is sufficient to form a group G for which the MCS can be set in accordance with the best channel quality of the wireless radio interface for these user devices 4A, 4C and 4D. Assuming that for the group G of devices consisting of user devices 4A, 4C and 4D, the channel quality is best for user device 4D (e.g. SINR reported by or derived for user device 4D exceeds SINR reported by or de- rived for user devices 4A and 4C), the MCS is set in accordance with the channel quality (e.g. the SINR) for user device 4D.
In a next step, S44, the telecommunications network 1 performs multicast transmission of the data in accordance with the selected MCS, i.e. in accordance with the MCS selected in accordance with the channel quality determined from the channel quality information reported by user device 4D.
This is indicated by the thick arrows in Fig. 4A. The lighter greyscale of the arrows indicates a greater likelihood that user devices 4A and 4C, for which a poorer channel quality was determined than for user device 4D, do not appropriately receive all the multicast data since the MCS is not selected in accordance with their channel quality.
The user device 4D transmits data parts (e.g. data packets or data segments) that has not been correctly received by user devices 4A, 4C from the telecommunication network's multicast transmission. The user device 4D transmits the data parts over the direct wireless connections, e.g. over D2D links.
Functional block 20 in the telecommunications network, e.g. located in an eNodeB, may decide when to switch from the prior art multicast method of selecting the MCS in accordance with a target SINR (which could be considered to correspond to a target channel quality) to the multicast method of selecting the MCS in accordance with the best channel quality as determined or derived from channel quality information received from a group of devices capable of distributing the multicast data over direct wireless connections within the group. A signal containing an indication of the application of the latter method is transmitted to the user devices. Functional block 21 in the user devices transmits at least one of channel quality information and direct connection information to the telecommunications network 1 in response to receiving the (instruction) signal containing the indication from the telecommunications network 1 .
Fig. 5 is a block diagram illustrating an exemplary data processing system 50 that may be used as a device 4A-4D comprising functional block 21 or as a network node containing functional block 20, e.g. an MCE, in the telecommunications network 1.
Data processing system 50 may include at least one processor 51 coupled to memory elements 52 through a system bus 53. As such, the data processing system 50 may store program code within memory elements 52. Further, processor 51 may execute the program code accessed from memory elements 52 via system bus 53. In one aspect, data processing system 50 may be implemented as a computer that is suitable for storing and/or executing program code. It should be appreciated, however, that data processing system 50 may be implemented in the form of any system including a processor and memory that is capable of performing the functions described within this disclosure.
Memory elements 52 may include one or more physical memory devices such as, for ex- ample, local memory 54 and one or more bulk storage devices 55. Local memory 54 may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive or other persistent data storage device. The data processing system 50 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the number of times program code must be retrieved from bulk storage device 55 during execution.
Input/output (I/O) devices depicted as input device 56 and output device 57 optionally can be coupled to the data processing system 50. Examples of input devices may include, but are not limited to, for example, a keyboard, a pointing device such as a mouse, a touchscreen, or the like. Examples of output device may include, but are not limited to, for example, a monitor or display, speakers, or the like.
Input device 56 and/or output device 57 may be coupled to data processing system 50 either directly or through intervening I/O controllers. A network adapter 58 may also be coupled to data processing system 50 to enable it to become coupled to other systems, computer systems, remote network devices, and/or remote storage devices through intervening private or public networks. The network adapter 58 may comprise a data receiver for receiving data that is transmitted by said systems, devices and/or networks to said data processing system 50 and a data transmitter for transmitting data to said systems, devices and/or networks. Modems, cable modems, and Ethernet cards are examples of different types of network adapters that may be used with data processing system 50.
As pictured in Fig. 5, memory elements 52 may store an application 59. It should be ap- preciated that data processing system 50 may further execute an operating system (not shown) that can facilitate execution of the application. Applications, being implemented in the form of executable program code, can be executed by data processing system 50, e.g., by processor 51. Responsive to executing the application 59, the data processing system 50 may be configured to perform one or more operations to be described herein in further detail.
In one aspect, for example, data processing system 50 may represent a client data processing system, e.g. within user devices 4A-4D. In that case, application 59 may represent a client application that, when executed, configures data processing system 50 to perform the various functions described herein for the device containing functional block 21. Examples of a client can include, but are not limited to, a personal computer, a portable computer, a mobile phone, or the like.
In another aspect, data processing system 50 may represent a network node containing functional block 20, e.g. an MCE or a base station in which case application 59, when executed, may configure data processing system 50 to perform operations as described in the present disclosure.
It is noted that the method has been described in terms of steps to be performed, but it is not to be construed that the steps described must be performed in the exact order described and/or one after another. One skilled in the art may envision to change the order of the steps and/or to perform steps in parallel to achieve equivalent technical results.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The
embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
Various embodiments of the invention may be implemented as a program product for use with a computer system or a processor, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media (generally referred to as "storage"), where, as used herein, the expression "non-transitory computer readable storage media" comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored.
Claims
1. A method for multicasting data for at least one first user device and at least one second user device from a telecommunications network over a wireless radio interface, wherein the first user device and the second user device are enabled to establish a connection with the telecommunications network over the wireless radio interface and to establish a direct wireless connection with each other, the method comprising the steps in the telecommunications network of:
receiving channel quality information from the first user device and the second user device, the channel quality information being indicative of a wireless channel quality of a wireless channel between the telecommunications network and the first user device and the second user device, respectively; determining from the received channel quality information that the wireless channel quality for the at least one first user device exceeds the wireless channel quality for the at least one second user device. selecting a modulation and coding scheme for multicast transmission of data in accordance with the wireless channel quality for the first user device;
performing multicast transmission of the data over the wireless radio interface in accordance with the selected modulation and coding scheme.
2. The method according to claim 1 , wherein the channel quality information received from the first user device and the second user device at least comprises a value indicative of a Signal-to-lnterference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel and the method further comprises the step of assessing the wireless channel quality on the basis of the value for the first user device and the second user device.
3. The method according to claim 1 or 2, further comprising the steps of:
receiving direct connection information from user devices being capable to establish a wireless direct connection with at least one user device;
registering the user devices being capable to establish a wireless direct connection with at least one user device as members of a group of user devices, the group of user devices comprising at least the first user device and the second user device as members of the group of user devices;
receiving the channel quality information from the user devices registered as members of the group of user devices,
determining from the received channel quality information that the wireless channel quality for the first user device exceeds the wireless channel quality for the remaining members of the group of user devices, the remaining members including the second user device;
selecting the modulation and coding scheme in accordance with the wireless channel quality for the first user device; and
performing multicast transmission of the data over the wireless radio interface in accordance with the selected modulation and coding scheme.
4. The method according to one or more of the preceding claims, further comprising the steps of:
obtaining indications from at least the first user device and the second user device indicating interest in obtaining the data via multicast;
registering the first user device and the second user device as members of a group of user devices in accordance with the obtained indications.
5. The method according to claim 3 or 4, further comprising the step of transmitting a request to registered members of the group of user devices to report at least one of the channel quality information and the direct connection information.
6. The method according to claim 5, further comprising the step of: transmitting the request including information indicating registered members of the group of user devices;
receiving direct connection information from the user devices with respect to only other user devices being registered members of the group of user devices.
7. The method according to one or more of the preceding claims, comprising the step of repeatedly, e.g. periodically, receiving, at least one of channel quality information from the first user device and the second user device and direct connection information from the first user device and the second user device, optionally in response to one or more corresponding requests from the telecommunications network to report the at least one of the channel quality information and the direct connection information.
8. A computer program comprising software code portions or a computer program product storing software code portions, the software code portions, when run on a computer system, being configured for executing the method according to one or more of the claims 1-7.
9. A system in a telecommunications network for multicasting data for at least one first user device and at least one second user device over a wireless radio interface, wherein the first user device and the second user device are enabled to establish a connection with the system over the wireless radio interface and to establish a direct wireless connection with each other, wherein the system is configured for:
receiving channel quality information from the first user device and the second user device, the channel quality information being indicative of a wireless channel quality of a wireless channel between the telecommunications network and the first user device and the second user device, respectively; determining from the received channel quality information that the wireless channel quality for the at least one first user device exceeds the wireless channel quality for the at least one second user device; selecting a modulation and coding scheme for multicast transmission of data in accordance with the wireless channel quality for the first user device;
performing multicast transmission of the data over the wireless radio interface in accordance with the selected modulation and coding scheme.
10. The system according to claim 9, wherein the channel quality information received from the first user device and the second user device at least comprises a value indicative of a Signal-to-lnterference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss on the wireless channel and assessing the wireless channel quality on the basis of the value for the first user device and the second user device.
1 1. The system according to claim 9 or 10, wherein the system is further configured for:
receiving direct connection information from user devices being capable to establish a wireless direct connection with at least one user device;
registering the user devices being capable to establish a wireless direct connection with at least one user device as members of a group of user devices, the group of user devices comprising at least the first user device and the second user device as members of the group of user devices;
receiving the channel quality information from the user devices registered as members of the group of user devices,
determining from the received channel quality information that the wireless channel quality for the first user device exceeds the wireless channel quality for the remaining members of the group of user devices, the remaining members including the second user device;
selecting the modulation and coding scheme in accordance with the wireless channel quality for the first user device; and
performing multicast transmission of the data over the wireless radio interface in accordance with the selected modulation and coding scheme.
12. The system according to one or more of the preceding claims 9-1 1 , wherein the system is further configured for:
obtaining indications from at least the first user device and the second user device indicating interest in obtaining the data via multicast;
registering the first user device and the second user device as members of a group of user devices in accordance with the obtained indications.
13. The system according to claim 1 1 or 12, wherein the system is further configured for transmitting a request to the registered members of the group of user devices to report at least one of the channel quality information and the direct connection information.
14. The system according to claim 13, wherein the system is further configured for: transmitting the request including information indicating registered members of the group of user devices;
receiving direct connection information from the user devices with respect to only other user devices being registered members of the group of user devices.
15. The system according to one or more of the preceding claims 8-12, wherein the system is further configured for repeatedly, e.g. periodically, receiving, at least one of channel quality information from the first user device and the second user device and direct connection information from the first user device and the second user device, optionally in response to one or more corresponding requests from the telecommunications network to report the at least one of the channel quality information and the direct connection information.
16. A user device configured for use with the system of one or more of the claims 8- 15, wherein the user device is configured for reporting to the telecommunications network direct connection information relating to user devices being capable to establish a wireless direct connection with the device.
17. The user device according to claim 16 comprising a receiver configured for receiving an instruction signal from the telecommunications network, wherein the instruction signal is indicative of a multicast state of the telecommunications network, the multicast state of the telecommunications network being that multicast of data is performed over the wireless radio interface for a group of user devices assisted by direct wireless device-to-device transmission of at least a part of the data and a processor being programmed for participating in the group of user devices to assist that all user devices of the group of user devices receive the data in response to the instruction signal.
18. An uplink channel associated with a downlink MBMS channel, the uplink channel being configured for containing channel quality information, e.g. periodic or requested channel quality information, indicative of a wireless channel quality of a wireless channel between a telecommunications network and a user device.
19. The uplink channel according to claim 18, wherein the channel quality information comprises a channel quality indictor CQI determined by a user device on the basis of an estimate of at least one of a Signal-to-lnterference plus Noise Ratio (SINR) value, a Reference Signal Received Power (RSRP) value, a Reference Signal Received Quality (RSRQ) value or a value relating to the estimate of path loss of a wireless channel.
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FR3066065A1 (en) * | 2017-05-04 | 2018-11-09 | Thales | METHOD AND SYSTEM FOR DISTRIBUTING IN A POINT-TO-MULTIPOINT AND POINT-TO-POINT (D2D) MIXED NETWORK |
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