AU2006203695A1 - Provision of downlink packet access services to user equipment in a spread spectrum communication network - Google Patents

Description

P/00/011 Regulation 32

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Provision of downlink packet access services to user equipment in a spread spectrum communication network The following statement is a full description of this invention, including the best method of performing it known to us: 004862301 O 2 PROVISION OF DOWNLINK PACKET ACCESS SERVICES TO USER EQUIPMENT IN A SPREAD SPECTRUM COMMUNICATION NETWORK The present invention relates generally to the provision of downlink packet access services to mobile station in a spread spectrum communication network. The invention

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1-1 is suitable for use in the provision of such services to user equipment in a communications network conforming to the 3 rd Generation Partnership Project, Long term evolution (3GPP-LTE) standards that are being developed, and it will be convenient to describe the invention in relation to this exemplary, but non-limiting, 0 application.

Recent enhancements packet transmissions such as High Speed Downlink Packet Access (HSDPA) and enhanced uplink technology have made 3GPP radio-access technology highly competitive. In order to ensure that the competitiveness of this technology continues over a long time frame, a long term evolution of 3GPP radioaccess technology is being developed. This new technology is known as Super 3G.

Important parts of the long term evolution of 3G-LTEtechnology will include Radio Access Network (RAN) latency reduction, higher user data rates, improving system capability and coverage, and reducing cost to a network operator. In order to achieve this, an evolution of the radio interface as well as the radio network architecture is being considered. The objective of this evolution is to develop a framework to enable high data rate, low-latency and packet-optimized radio-access.

Development of the 3G-LTEsystem has been focused on supporting services provided by the PS-domain, such as enhanced HSDPA, Multimedia Broadcast Multicast Services (MBMS), High Speed Uplink Packet Access (HSUPA) and other similar types of packet switched services including Voice Over IP.

Existing HSDPA services in Wideband Code Division Multiple Access (WCDMA) systems are currently provided in a manner that is dependent on other dedicated RAN services. This results in an extremely complicated protocol stack design and hinders the development of WCDMA HSDPA services. The 3G-LTEsystem will be developed to support enhanced HSDPA and other types of packet switched services. However, reusing the existing HSDPA related procedures that have been developed for the WCDMA system will lead to a situation where the future 3G system shall be coupled with and operationally dependent on existing WCDMA technology. This interdependence is likely to result in an even more complicated RAN architecture, which will then increase the cost of design, manufacture and operation of the 3G-LTEsystem.

There therefore exists a need to enable enhanced HSDPA services to be introduced into the future 3G-LTEsystem in such a manner as to be able to operate independently from the existing 3G-WCDMA system when considered from the RAN perspective.

There also exists a need to provide enhanced HSDPA services in a manner that ameliorates or overcomes HSDPA service provision techniques.

In one aspect of the present invention provides a method of providing a packetised data transmission service to a mobile terminal in a spread spectrum communication network, the method including: at a transmitter, broadcasting an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetised data transmission service intended for the mobile terminal; at the mobile terminal, monitoring the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter on an uplink contention channel; and at the transmitter, upon contention completion, transmitting packetised data transmission service configuration information to the mobile terminal on the broadcast channel.

Preferably, the method further includes the step of periodically placing the mobile terminal in an active to monitor the broadcast channel for the indication message, and if no indication message is detected, placing the mobile terminal in an inactive state.

oeMSI"e2 4 The method may include the step of at the transmitter, transmitting control information for the packetised data transmission service to the mobile terminalmobile terminal on a downlink shared control channel.

The method may include the step of at the transmitter, transmitting data for the packetised data transmission service to the mobile terminal on a downlink shared data channel.

The method may include the step of at the mobile terminal, transmitting channel quality measurement and reporting information to the transmitter on an uplink shared schedule channel.

The method may further include the steps of: ceasing transmission from the transmitter of packetised data transmission control information to the mobile terminal, and upon failure to detect packetised data transmission control information at the mobile terminal within a predetermined time, terminating the packetised data transmission service.

Alternatively, the method may include the steps of; at the transmitter, notifying the mobile terminal to terminate the packetised data transmission service by inclusion of a termination message in a packet header of an packetised data transmission control information packet; and upon detection of the termination message at the mobile terminal, terminating the packetised data transmission service.

Another aspect of the invention provides a system for providing a packetised data transmission service in a spread spectrum communication network, the system including a transmitter and mobile terminal, the transmitter being adapted to broadcast an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetised data transmission service intended for the mobile terminal; 00"851te8 O the mobile terminal being adapted to monitor the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter on an uplink contention channel; and the transmitter being further adapted, upon contention completion, to transmit 5 packetised data transmission service configuration information to the mobile terminal on the broadcast channel.

(Ni O The present invention will now be described in reference to the attached drawings in which a method and system of providing a High Speed Downlink Packet Access (HSDPA) service is illustrated as a preferred embodiment. It is to be appreciated that the invention is not to be construed as being limited to the particular embodiment illustrated in the drawings.

In the drawings: Figure 1 is a schematic diagram illustrating a spread spectrum communication system in which an HSDPA service is provided from a BTS to UE; and Figure 2 is a timing diagram illustrating the functional steps performed at both the BTS and UE during notification, acknowledgement, performance and termination of the HSDPA service.

Referring now to Figure 1, there is shown generally a spread spectrum communication network 100 including a base transceiver station 102 operably connected to a radio transmission tower 104. The Base Transceiver Station (BTS) and radio tower are operably connected to a communications network conforming to the 3G-LTEsystem being developed by the 3GPP. The BTS communicates with user equipment 108 whilst the user equipment is located within a broadcast cell 110. Control information and data is exchanged between the BTS 102 and user equipment 108 during the provision of High Speed Downlink Packet Access (HSDPA) services by means of a channel structure 112 including a downlink broadcast channel 114, an uplink reserved channel (contention) 116, a downlink shared control channel 118, a downlink shared data 4 channel 120 and an uplink scheduled channel (shared control channel and physical S control channel) 122.

Referring now to Figure 2, when the user equipment 108 moves within the broadcast cell 110, both the BTS 102 and UE 108 act at step 200 to allow the UE to register with C* 5 the 3G-LTEnetwork 106 and thereby enable the BTS 102 to communicate directly with the user equipment 108. At step 202, the BTS 102 transmits synchronisation Sinformation to the UE 108 on a synchronisation channel/common pilot channel in order Sfor the UE 108 to detect relevant information sent to the UE in data packets.

Upon receipt of the synchronisation information at step 202, the UE 108 performs, at step 204, cell search, frame timing detection, symbol timing and scrambling code detection functions in accordance with conventional WCDMA techniques to enable communication to be established between the 3G-LTEnetwork 106 and the UE 108.

When an HSDPA service is to be provided to UE 108, an indication message is prepared at step 206 to be broadcast to the entire cell 110, the indication message being encoded in such way that it can be decoded and identified by the UE 108 by a specific UE identification number that is allocated to the UE 108 by the network at step 200. The indication message acts to notify the UE 108 of an available HSDPA services intended for that UE. The encoded information is then broadcast at step 208 on the broadcast channel 114 (set of sub-carriers), the UE 108 being informed of the broadcast channel 114 upon registration with the network 106 at step 200. At step 210, the UE 108 is normally in an inactive state, except for predetermined periods to time when, in step 212, the UE 108 is placed in an active state in order to monitor the broadcast channel 114 for indication messages from the BTS 102. If no indication message is detected, the UE 108 is once again placed in an inactive state. However, if an indication message is detected, the UE 108 processes the indication message and transmits an acknowledgement of detection of the indication message to the BTS 102 on the uplink reserved channel 116 using a contention approach. The uplink reserved channel information on which the acknowledgement 214 is transmitted is indicated to the UE 108 in the indication message 208.

The BTS 102 monitors the reserved channel 116 at step 216 for the acknowledgement 214. Upon receipt of the acknowledgement from the UE 108, the BTS 102 informs the UE 108 about the contention completion, and starts to prepare and transmit the RAN HSDPA service configuration information 218 on the downlink broadcast channel 114, at a time and frequency allocated for this task. This DL broadcast channel is monitored only by the UE(s) that previously sent an acknowledgement to the indication message.

Upon successful completion of the contention, the UE 108 prepares to receive data on the downlink broadcast channel 114 at a predetermined time after completion of the contention, at step 220. The configuration information received on this channel assists the UE 108 to perform layer 1 (physical layer), layer 2 (medium access control/radio link control) and layer 3 (Radio Resource Control layer) configuration to monitor the downlink shared control channel 118, configuring the Hybrid Automatic Repeat Request (HARQ) related functions and performing channel quality measurement and reporting.

Once the configuration has taken place at step 220, the UE 108 starts performing, at step 222, channel quality measurement, and monitoring of the downlink shared control channel 118 to detect fast signalling intended for the UE 108 and other existing HSDPA related procedures for receiving data on the shared data channel 120.

Accordingly, channel quality information 224 is transmitted from the UE 108 to the BTS 102 according to a preconfigured schedule in order to provide the BTS 102 with information as to which frequency chunk in the downlink shared data channel 120 is best suited for the particular user equipment 108 in order that frequency scheduling can be optimised. The channel quality information is transmitted on the uplink schedule channel 122. Once the BTS 102 has received initial channel quality information, the BTS, at step 226, performs channel scheduling and sends fast signalling information 228 on the shared control channel 118 to the UE 108. The associated packet data 230 is then sent on the shared data channel 120 to the UE 108. At step 232, the UE 108 keeps monitoring the share control channel 118 on the allocated time-frequency slot.

Once the UE 108 detects control information intended for that UE, it starts to receive and decode the associated data 230 transmitted on the shared data channel 120. The result of the data packet reception (ACK/NACK/POST/PRE/DTX for H-ARQ processing) 234 is then reported to the BTS 102 on the associated uplink scheduled channel 122.

Similarly, the channel quality information 236 for the downlink packet scheduling is O 8 again transmitted on the uplink scheduled channel 122. At step 238, once the H-ARQ S feedback information and CQI information has been received, the BTS 102 performs Adaptive Modulation and Coding (AMC), scheduling and retransmission for each user.

Retransmission occurs if a NACK message is received from the user equipment 108.

Steps 228 to 238 are then repeated at both the BTS 102 and UE 108 during provision of

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the HSDPA service to the user equipment 108.

Once the HSDPA service provided to the UE 108 is to be terminated, the BTS 102 may N simply stop transmission of control information on the shared control channel 118 to the UE 108, at step 240. In this case, upon failure of the UE 108 at step 242 to detect HSDPA control information within a predetermined time, the HSDPA service is terminated and the UE 108 is again placed in an inactive state. Alternatively, the HSDPA service can be terminated by inclusion of the termination message in a packet header of an HSDPA control information packet sent to the UE 108 on the downlink shared data channel 120. Upon detection of the termination message at the UE 108, the HSDPA service may be terminated.

From the foregoing, it will be appreciate that the above described method for providing an HSDPA service to user equipment advantageously introduces a specific paging procedure and specific paging indication for an HSDPA service without requiring use of a dedicated data channel as currently described in WCDMA networks. Moreover, the above described method introduces a sleep mode to allow the 3G-LTEuser equipment to save power when in use. A new channel is introduced to establish the Radio Resource Control (RRC) layer peer to peer communication for HSDPA RAN configuration, rather than relying upon a dedicated channel as in current WCDMA systems.

A packet transmission termination scheme is also introduced at the radio interface level to allow either the base transceiver station to terminate a downlink packet transmission either temporarily or permanently whilst minimising the exchange of traffic via the air interface between the base transceiver station and the user equipment.

94854862, IND 9 Finally, it is to be appreciated that various modifications and additions may be made to ;Z the above described method of providing a high speed downlink packet access service to user equipment in the spread spectrum communication network without departing from the spirit or ambit of the invention.

Claims (8)

1. A method of providing a packetised data transmission service to a mobile terminal in a spread spectrum communication network, the method including: at a transmitter, broadcasting an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetised data transmission service intended for the mobile terminal; at the mobile terminal, monitoring the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter on an uplink contention channel; and at the transmitter, upon contention completion, transmitting packetised data transmission service configuration information to the mobile terminal on the broadcast channel.

2. A method according to claim 1, and further including the steps of: periodically placing the mobile terminal in an active state to monitor the broadcast channel for the indication message, and if no indication message is detected, placing the mobile terminal in an inactive state.

3. A method according to either one of claims 1 or 2, and further including the step of: at the transmitter, transmitting control information for the packetised data transmission service to the mobile terminal on a downlink shared control channel.

4. A method according to any one of the preceding claims, and further including the step of: at the transmitter, transmitting data for the packetised data transmission service to the mobile terminal on a downlink shared data channel.

5. A method according to any one of the preceding claims, and further including the step of: IND1 at the mobile terminal, transmitting channel quality measurement and reporting information to the transmitter on an uplink shared scheduled channel.

6. A method according to any one of the preceding claims, and further including the steps of: ceasing transmission from the transmitter of packetised data transmission control 0 information to the mobile terminal, and (N IND upon failure to detect packetised data transmission control information at the 0 mobile terminal within a predetermined time, terminating the packetised data transmission service.

7. A method according to any one of claims 1 to 5, and further including the steps of: at the transmitter, notifying the mobile terminal to terminate the packetised data transmission service by inclusion of a termination message in a packet header of an packetised data transmission control information packet; and upon detection of the termination message at the mobile terminal, terminating the packetised data transmission service.

8. A system for providing a packetised data transmission service in a spread spectrum communication network, the system including a transmitter and mobile terminal, the transmitter being adapted to broadcast an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetised data transmission service intended for the mobile terminal; the mobile terminal being adapted to monitor the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter on an uplink contention channel; and

8844362- 12 the transmitter being further adapted, upon contention completion, to transmit packetised data transmission service configuration information to the mobile terminal on the broadcast channel. Dated 23 August 2006 Freehills Patent Trade Mark Attorneys Patent Trade Mark Attorneys for the Applicant: NEC AUSTRALIA PTY LTD