WO2009147643A2

WO2009147643A2 - Communication methods, a communication device, and a communication apparatus

Info

Publication number: WO2009147643A2
Application number: PCT/IB2009/052391
Authority: WO
Inventors: Poovandhran Chetty
Original assignee: Poovandhran Chetty
Priority date: 2008-06-05
Filing date: 2009-06-05
Publication date: 2009-12-10
Also published as: WO2009147643A3

Abstract

THIS invention relates to a method of transmitting data in a communication system, to a method of receiving data in a communication system, to a communication device, and to an apparatus operable to initiate or facilitate a single data communication session between at least two communications devices or terminals. The method of transmitting data from a communication device in a communication system comprises simultaneously transmitting data from the communication device over at least two independent communication networks in parallel, the at least two independent communication networks being operated by at least two independent communication network operators respectively.

Description

COMMUNICATION METHODS, A COMMUNICATION DEVICE, AND A COMMUNICATION APPARATUS

BACKGROUND OF THE INVENTION

THIS invention relates to a method of transmitting data in a communication system, to a method of receiving data in a communication system, to a communication device, and to an apparatus operable to initiate or facilitate a single data communication session between at least two communications devices or terminals.

Mobile commercial media solutions, for example for voice, data and video, are typically provided by licensed Mobile Network Operators (MNO) and Mobile Virtual Network Operators (MVNOs). Network operators are in a position to offer high levels of quality of service (QoS) as they own the network infrastructure or in the case of MVNO's are licensed to use the network infrastructure. There are other licensed telecommunication service providers, for example Value Added Network Services (VANS), whom are permitted to offer mobile commercial media solutions but have no ownership or influence of the network infrastructure.

It follows that VANS typically offer commercial media solutions in unmanaged or uncontrolled wireless network environments. This presents problems or challenges to the VANS in respect of providing acceptable levels of QoS for commercial solutions. It is an object of the present invention to at least address these problems or challenges.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a method of transmitting data from a communication device in a communication system, the method comprising simultaneously transmitting data from the communication device over at least two independent communication networks in parallel, the at least two independent communication networks being operated by at least two independent communication network operators respectively.

The single data communication session may include media, and signal transmissions over at least two independent communication networks

In one example embodiment, media may include Voice over IP.

The method may comprise:

packetizing the data to be transmitted into data packets; and

transmitting the data packets from the communication device over the at least two independent communication networks in parallel.

The method may further comprise: monitoring the at least two independent communication networks for the independent communication network with the best Quality of Service (QoS).

using the independent communication network with the best QoS as a primary channel for transmission of data packets; and using the other independent communication network as a secondary channel for parallel transmission of data packets.

The selection of the primary and secondary channels may change over time.

In an example embodiment, the method may also comprise selecting the independent communication network with one or a combination of lowest packet loss, best signal strength or lowest latency as the independent communication network with the best QoS.

The method may further comprise using the secondary channel at least to provide partial or full independent redundancy or increased independent capacity, or a combination thereof, to the primary channel.

The methods may comprise using data packets sent on the secondary channel to provide increased independent redundancy to the primary channel.

The increased independent redundancy from the secondary channel may typically be used for reconstruction of lost data packets or error correction of data packets from the primary channel.

The primary channel may be used for partial redundancy.

The method may comprise:

initiating a single data communication session over at least two independent telecommunication networks; and

transmitting the data in parallel from the communication device in the single data communication session over the respective independent communication networks. -A-

The method may comprise transmitting signals over the primary channel, secondary channel or both primary and secondary channel respectively.

The method may also comprise:

processing data to be transmitted into frames;

encoding each frame; and

transmitting the encoded frames in parallel over the at least two independent communication networks as data packet streams.

In an example embodiment, the method may comprise:

selecting, on notification, the independent communication network which provides the best QoS as the primary channel for transmission of data packets; and

transmitting the data packet streams in parallel over the primary and secondary channels in the single data communication session .

The at least two independent communication networks may be independent wireless or mobile telecommunication networks, fixed telecommunication networks, or a combination of a wireless -or mobile telecommunication network and a fixed telecommunication network respectively.

The single data communication session may comprise one or a combination of a Session Initiation Protocol (SIP) session, and other data session.

The data communication session may comprise a signaling and media session. According to a second aspect of the invention, there is provided a method of receiving data in a communication system, for single data communication session, the method comprising:

receiving data, at a communication device, over at least two independent communication networks, the independent communication networks being operated by at least two independent network operators respectively;

monitoring the at least two independent communication networks for the network which provides the best QoS;

selecting the independent communication network which provides the best QoS at a particular time as a primary channel for reception of the data, the other independent communication network being a secondary channel for reception of the data; and

establishing a single data communication session over both the primary and secondary channels.

The method may also comprise using data received via the secondary channel to increase independent redundancy to the primary channel.

The method may further comprise of receiving data - in the form of data packets in any configuration, setting, format or scheme on the secondary channel so as at least to increase redundancy independently.

The method may comprise reconstructing lost data packets from the primary channel using data packets received via the secondary channel.

The method may comprise reconstructing lost data packets from both the primary and secondary channels. The method may comprise using the secondary channel to provide additional capacity to the primary channel, the additional capacity being used at least for other data transmissions.

Other data transmissions maybe any media other than Voice over IP in a single data communication session

The single data communication session may conveniently comprise any media and signaling.

According to a third aspect of the invention, there is provided a communication device comprising:

at least one communication module to allow the communication device to communicate over at least two independent communication networks, the independent communication networks being operated by at least two independent network operators respectively; and

a transmission module arranged to transmit simultaneously, from the device via the respective at least one communication module, data over the at least two independent communication networks in parallel in a single data communication session.

The communication device may further comprise:

a receiver module communicatively coupled to the communication module, the receiver module being arranged to receive data over the at least two independent communication networks for a single data communication session;

a monitoring module arranged to monitor the at least two independent communication networks for the network which provides the best QoS; and a selection module communicatively coupled to the monitoring module, the selection module being arranged to select the independent communication network which provides the best QoS at a particular time as a primary channel for communication, the other independent communication network being a secondary channel for communication.

It will be appreciated that the communication device may be arranged to establish a single communication session over the primary channel, secondary channel, or both primary and secondary channels together. The data communication session may comprise any media or signaling.

The transmission module may be configured to transmit redundant data on the secondary channel.

The receiver module may be arranged to use data received from the secondary channel to increase independently redundancy to the primary channel.

The transmission module and the receiver module may be configured to transmit and receive data comprising data packets in any configuration, setting, format or scheme respectively.

The receiver module may be arranged to use the secondary channel at least to provide additional capacity to the primary channel.

According to a fourth aspect of the invention, there is provided an apparatus operable to initiate or facilitate a single data communication session between at least two communications devices or terminals, the apparatus comprising:

a transmission module arranged to transmit data received from each device or terminal over at least two independent communication networks, the independent communication networks being operated by at least two independent network operators respectively for a single data communication session;

a receiver module arranged to receive data from each device or terminal over at least two independent communication networks, the independent communication networks being operated by at least two independent network operators respectively for a single data communication session; and

a monitoring module arranged to monitor the communication network which provides the best QoS, the communication network providing the best QoS being a primary channel and the other communication network being a secondary channel.

The transmission and receiver modules may be configured for error correction or reconstruction of lost data form bother the primary and secondary channels prior to any further transmission on the primary and secondary channels.

The data transmitted and received by the transmission module and receiver module respectively may typically comprise data packets.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic diagram of a system in accordance with an example embodiment;

Figure 2 shows a schematic diagram of a device of the system illustrated in Figure 1 in more detail;

Figure 3 shows a flow diagram of a method in accordance with an example embodiment; Figure 4 shows a schematic block diagram of the encoding of speech to media frames in accordance with an example embodiment;

Figure 5 shows a schematic diagram of a media packet in accordance with an example embodiment;

Figure 6 shows a schematic diagram of a media packet stream in accordance with an example embodiment;

Figure 7 shows a schematic diagram of two media packet streams from or receivable by for example a device of the system of Figure 1;

Figure 8 shows another schematic diagram of two media packet streams from or receivable by for example a device of the system of Figure 1 ;

Figure 9 shows yet another schematic diagram of two media packet streams from or receivable by for example a device of the system of Figure 1;

Figure 10 shows another schematic diagram of two media packet streams from or receivable by for example a device of the system of Figure 1 ;

Figure 11 shows a flow diagram of another method in accordance with an example embodiment; and

Figure 12 shows a schematic diagram of two media packet streams receivable by for example a device of the system of Figure 1 and the combination of the two streams in accordance with an example embodiment. DESCRIPTION OF PREFERRED EMBODIMENTS

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of an embodiment of the present disclosure. It will be evident, however, to one skilled in the art that the present disclosure may be practiced without these specific details.

Referring now to Figures 1 and 2 of the drawings, a system in accordance with an example embodiment is generally indicated by reference numeral 10. The system 10 includes a plurality of communication devices such as mobile communication client devices or terminals 12. For ease of illustration, only two devices 12a and 12b are shown. These devices 12 are typically cellular telephones, personal digital assistants, mobile computer terminals for example a PC (Personal Computer) or laptop, or the like. It will be understood that the devices and components thereof shall be indicated by collective reference numerals, for example reference numeral 12. However, for purposes of explanation, each individual device illustrated and respective components thereof will be indicated by collective reference numerals with letters appended thereto, for example 12a and 12b as illustrated.

The devices 12 are arranged to communicate with each other via at least two independent communication networks 14 and 16 respectively. For ease of explanation, the communication networks 14 and 16 are wireless communication networks. In this regard, the wireless communication networks 14 and 16 may be any wireless communication networks for example packet-switched networks and may form part of the Internet. Instead, the communication networks 14 and 16 may be circuit switched networks, public switched data networks, or the like. In this particular example embodiment, the communication networks 14 and 16 are Packet Radio Data Networks, including but not limited to GPRS (General packet radio service), 3G, HSPDA (High-Speed Downlink Packet Access), EDGE (Enhanced Data Rates for GSM Evolution, WiMAX (Worldwide Interoperability for Microwave Access), Wi-Fi, or the like. The first communication network 14 may be a network operated by a first network operator and the second communication network 16 may be a network operated by a second network operator.

In other example embodiments 9 (not shown), at least one of the communication networks may be a fixed network for example a PSTN (Public Switched Telephone Network), DSL (Digital Subscriber Line) networks, or the like.

The communication system may conveniently be a VoIP (Voice over Internet Protocol) system, for example PTT (push to talk).

The device 12 may include two communication modules in the form of modems 18 and 20, the modems 18, 20 being arranged to communicate simultaneously over the communication networks 14 and 16 respectively. It will be understood that the modem 18 is able to communicate over the communication network 14 or 16 and the modem 20 is able to communicate over the communication network 14 or 16. In other example embodiments, the device 12 may include two modems operable to communicate simultaneously over the two communication networks 14 and 16.

It will be appreciated that in an example embodiment, the modem 18 may be arranged to communicate over both networks 14 and 16 respectively (shown in broken lines).

The device 12 includes a plurality of modules as illustrated in Figure 2. It will be noted that, for the purposes of this specification, the term "module" includes an identifiable portion of code, computational or executable instructions, data, or computational object to achieve a particular function, operation, processing, or procedure. A module need not be implemented in software; a module may be implemented in software, hardware, or a combination of software and hardware. Further, a module need not be incorporated in the device 12 but may be provided or may reside in the system 10 such that the device 12 is able to use the functionality provided by a module from within the system 10.

In particular, the device 12 includes a transmission module 22 arranged to transmit simultaneously from the device 12, via the respective modems 18 and 20, data as data packets over the two communication networks 14 and 16.

The device 12 also includes a receiver module 24 communicatively coupled to the modems 18 and 20, the receiver module being arranged to receive data packets over the communication networks 14 and 16 respectively.

The device 12 further includes a monitoring module 26 arranged to monitor the wireless communication networks 14 and 16, in particular the data received by the receiver module 24, to determine which of the two communication networks 14 or 16 provides the best Quality of Service (QoS). The communication network 14 or 16 which provides the best QoS is therefore understood to be a primary channel for communication while the other communication network 14 or 16 is understood to be a secondary channel for communication. In an example embodiment where more than two independent wireless communication networks are used, it follows that there may be correspondingly a plurality of primary channels or secondary channels. QoS may be understood to include transmission of packets with the least delay, packet loss or jitter resulting in perceptual speech quality of data communicated over the respective channels. It follows that the monitoring module 26 is arranged to monitor the networks 14 and 16 for the network with at least one or a combination of the lowest packet loss, best signal strength, or lowest latency. The network with at least one or a combination of the lowest packet loss, best signal strength, or lowest latency being selected as the primary channel. Since the monitoring module 26 is continually monitoring the networks 14 and 16 for the parameters described above, the primary and secondary channels may change over time.

It will be noted that the monitoring module 26 may make use of a Real Time Control Protocol (RTCP), or the like to determine the network 14 or 16 which provides the best QoS.

The device 12 also includes a selection module 28 communicatively coupled to the monitoring module 26, the selection module 28 being arranged to select the communication network 14 or 16 which provides the best QoS at a particular time, in other words, the primary channel at a particular time. It follows that the device 12 is operable to establish a communication session, in particular a session initiation protocol (SIP) session, over the primary channel. It will be noted that in certain example embodiments, the device 12 may be assigned two or more Internet Protocol (IP) addresses for each wireless communication network 14 and 16 for a single SIP session. It follows that two or more IP connections to the communication networks 14 and 16 are established for a single SIP session.

The transmission module 22 includes an encoder to encode speech into frames for transmission from the device 12. The frames may be arranged into data packets, and the data packets may be transmitted as a data packet stream, as will be discussed below.

The transmission module 22 is operable to transmit the packet stream in parallel over the wireless communication networks 14 and 16 by way of the modems 18 and 20 respectively. It will be noted that the transmission module 22 is communicatively coupled to the selection module 28 such that it is arranged to transmit packets in any configuration, settings, format or scheme over the respective primary and secondary channels. The module 28 may be arranged to transmit redundant data on the secondary channel. The receiver module 24 is also communicatively coupled to the monitoring module 26 such that it is operable to use data packets received from the secondary channel to, partially or fully, increase independent redundancy to the primary channel. In this regard, it will be noted that data in the secondary channel provides or increases redundancy to the primary channel in an independent fashion. In this regard, in order to increase independent redundancy, the receiver module 24 is arranged to receive in any configuration, setting, format or scheme data packets from the secondary channel. In this regard, in an example embodiment, the receiver module 24 is further arranged to receive in any configuration, setting, format or scheme data packets from the secondary channel and in an example embodiment, the primary channel.

In an example embodiment, the receiver module 24 is arranged to reconstruct lost data packets using data packets received from both the primary and the secondary channel.

It will be appreciated that the receiver module 24 is further arranged to use the secondary channel to provide additional capacity to the primary channel. In an example embodiment, increased capacity obtained may be utilised for additional data transmissions.

In an example embodiment the transmission module 22, receiver module 24, monitoring module 26, and selection module 28 may be provided in a processor (not shown) of the device 12. In this regard, device 12 may include a machine-readable medium, e.g. memory in the processor, main memory, flash memory, Random Access Memory (RAM) and/or hard disk drive, which carries a set of instructions to direct the operation of the processor. It is to be understood that the processor may be one or more microprocessors, controllers, or any other suitable computing device, resource, hardware, software, or embedded logic.

The device 12 may also include components which are not discussed in detail, or illustrated as the case may be, for example a display, keyboard or keypad, power supply, or the like. The device 12 may also include a Bluetooth module and WiFi module operable to allow the device to communicate over the respective wireless channels. In certain example embodiments, the device 12 also includes a Global Positioning System (GPS) module.

In a preferred example embodiment, the device 12 advantageously comprises an error correction module 29 arranged to perform an error correcting function or apply an error correction algorithm to the transmitted and/or received data. The error correction module 29 may be configured for error correction or reconstruction of lost packets based on data packets received from both the primary and the secondary channel.

It will be noted that in an example embodiment, the system 10 includes an apparatus operable to initiate or facilitate a single data communication session between the communications devices 12. The apparatus may conveniently comprise a server 30 (Figure 1 ). The server 30 is arranged to transfer and receive data packets between the devices 12 over the wireless communication networks 14 and 16 via Access Point Names (APN) 31. In this particular example embodiment, the system 10 is typically a peer-to- peer system whereby the devices 12a and 12b are operable to communicate with each other independently from the server 30. Instead, or in addition, the devices 12a and 12b communicate with each other by way of the server 30, the server 30 being arranged to initiate and/or facilitate a SIP session between the devices 12a and 12b.

In this regard, the server 30 typically includes a transmission module 32, receiver module 34, monitoring module 36, and a selection module 38. It will be appreciated that these modules are functionally similar to the modules of like name in the device 12 namely, the transmission module 22, receiver module 24, monitoring module 26, and a selection module 28. In addition, the server 30 includes an error correction module 39 operable to correct errors in data packets received from both the primary channel and the secondary channel. The module 39 may be similar to the module 29. In an example embodiment, the device 12 may be operable to establish a SIP session with the server 30 using any one of the networks 14 or 16 or both. In this regard, the selection module 28 of the device 12 is arranged to select the network 14 or 16 with the best QoS or even the network 14 or 16 with the highest radio signal strength as the primary channel to establish the SIP session. Instead, or in addition, the selection of the primary channel for establishment of the SIP session may be done by the selection module 38 of the server 30.

In a particular example embodiment, the device 12 is arranged to send and receive Real Time Protocol (RTP) packets to and from the server 30 over the networks 14 and 16 on a regular basis, for example every minute. The monitoring module 26 is typically arranged to facilitate this and it follows that data associated with the transmission and receipt of the RTP packets over each network 14 or 16 is used by the monitoring module 26 to determine which network 14 or 16 provides the best QoS. The data associated with the transmission and receipt of the RTP packets includes data indicative of delay, packet loss and jitter for each network 14 or 16.

Instead, or in addition, the monitoring module 36 of the server 30 is arranged to send and receive RTP packets to the device 12, in a similar fashion as described above, to determine which network 14 or 16 provides the best QoS.

In other example embodiments, the network 14 or 16 with the best quality of service is selected by using data associated with media data packets obtained at the start of a communication session.

During a communication session, viz. the SIP session, the server 30 is arranged to monitor the networks 14 and 16 by way of the monitoring module 36 for the network 14 or 16 which provides the best uplink thereto, or QoS, using RTCP in a similar fashion to the monitoring module 26 as hereinbefore described. In this regard, the server 30 is configured to report back to the device 12 information indicative of the network 14 or 16 which provides best uplink thereto, or QoS. In response to receiving such information from the server 30, the device 30 correspondingly is operable to change the primary or secondary channels for communication accordingly.

Similarly, both devices 12a and 12b are arranged to report back to the server 30 which network 14 or 16 provides best QoS so that the server 30 knows which of the networks 14 or 16 to use for downlink purposes at a particular time.

In this way, during a SIP session, the primary and secondary channels for communication may change between the communications networks 14 and 16 depending on the QoS provided by the respective networks 14 and 16 at a particular time. This ensures that during a SIP session, the primary channel is the network 14 or 16 which provides the best QoS.

Example embodiments will now be further described in use with reference to Figures 3 to 12. The example methods and examples shown in Figures 3 to 12 are described with reference to Figures 1 and 2, although it is to be appreciated that the example methods may be applicable to other systems (not illustrated) as well.

Referring firstly to Figures 3 to 10 of the drawings, a flow diagram of a method in accordance with an example embodiment is generally indicated by reference numeral 40 (Figure 3). When a user (not shown) wishes to initiate a communication session between their device 12a and the target device 12b, they initiate the call on their device 12a and begin talking on their device 12a. It follows that the method 40 comprises establishing, at block 41 , a connection over the two independent communication networks 14 and 16. The connection may typically be a SIP session.

The method 40 then comprises processing, at block 42, data in the form of the user's speech into frames and encoding each frame. Referring to Figure 4, the speech is encoded by an Adaptive Multi-Rate Narrow Band (AMR-NB) encoder 50, typically provided at the transmission module 22a, to produce an encoded speech frame 52. The encoded speech frame comprises most important bits 52.1 , important bits 52.2, or least important bits 52.3. It follows that each frame 52 is combined into a reai-time protocol (RTP) data packet 54 (Figure 5). Also, it will be understood that the packets 54 are combined into a RTP media data packet stream 56 (Figure 6) for transmission from the device 12a as will be described below.

The method 40 further comprises detecting, at block 44 (Figure 3), which communication network 14 or 16 has the best QoS. This is typically done by way of the monitoring module 36 in, for example, a manner as hereinbefore described. In other example embodiments, this may be done by way of the monitoring modules 26, for example monitoring module 26a. It follows that the method 40 also includes, at block 44, the step of selecting the communication network 14 or 16 with the best QoS as the primary channel for transmission of the data. This is typically done by way the selection module 38 of the server 30. However, in other example embodiments, the selection module 28a of the device 12a is arranged to select the primary channel.

If, for example, the communication network with the best QoS is communication network 14, it follows that the communication network 14 is the primary channel for transmission of media. The method then includes transmitting by way of the transmission module 22a, at block 46, data in the form of data packet streams 56, for example RTP data packet streams, over the primary channel via modem 18a. Simultaneously in the same SIP session, the transmission module 22a also transmits data packet streams over communication network 16 viz. the secondary channel, via modem 20a.

Referring now to Figures 7 to 10 in particular, it will be understood that the transmission module 22a is arranged to transmit data packet streams in various forms via the two modems 18a and 20a. For example, the transmission module 22a is arranged to transmit data packet streams in the form as illustrated in Figure 7, with a view to increase independent capacity of data which can be transmitted by the device 12a. In this particular example embodiment, the data packets to be transmitted are split between the two modems 18a and 20a for transmission thereof. It will be noted that in Figures 7 to 10, modem 1 corresponds to modem 18 and modem 2 corresponds to modem 20. In an example embodiment, increased capacity may be obtained by -by transmitting other data on the secondary channel.

In Figure 8, the transmission module 22a is arranged to transmit simultaneously the same packet data streams in parallel over the two communication networks 14 and 16 thereby to increase redundancy independently by way of the secondary channel.

The transmission module 22a may optionally transmit the original data packet stream over the communication network 14 via the associated modem 18a and may transmit only the most important bits from the original data stream over the communication network 16 via modem 20a at a reduced bit rate. In this particular example embodiment, the communication network 14 is correspondingly the primary channel whereas the communication network 16 is the secondary channel. This is illustrated in Figures 9 and 10.

Referring now to Figures 7 to 12 of the drawings, where in Figure 11 a flow diagram of a method in accordance with an example embodiment is generally indicated by reference numeral 60. It will be understood that the target device 12b which the user wants to initiate the communication session with will receive the data streams transmitted by the device 12a via the communication networks 14 and 16, in particular by way of modems 18b and 20b associated with the device 12b and also via the server 30.

In any event, the method 60 comprises monitoring, at block 62 by way of the monitoring module 36 of the server 30, the communication networks 14 and 16 for the communication network 14 or 16 which provides the best QoS. This is done in a similar fashion as hereinbefore described. It will again be noted that in the absence of the server 30, in a peer-to-peer communication session, the monitoring module 26b of the receiving device 12b may be operable to determine which network 14 or 16 provides the best QoS.

The method 60 then includes selecting, at block 63 by way of the selection module 38 of the server 30, the communication network 14 or 16 which provides the best QoS. Also, in an example embodiment, for example in the absence of the server 30, the selection module 28b of the receiver device 12b may be used to select the communication network 14 or 16 with the best QoS as the primary channel.

The method 60 then comprises receiving by way of the receiver module 24b of the device 12b, at block 64, data packet streams 56 over the communication networks 14 and 16 transmitted from the transmission module 22a of the device 12a via modems 18b and 20b respectively in parallel.

The method 60 comprises decoding, at block 65, the received frames from the received data packet streams.

The method 60 then comprises performing error correction, at block 66, of the received data packet streams as hereinbefore described by way of modules 29b and 39 respectively.

It follows that if network 14 is the network with best QoS, then the method 60 includes establishing, at block 68, a communications session, typically a SIP session, between the devices 12a and 12b using the communication network 14 or network 16 or both network 14 and 16 together for a single data communication session.. It is via the single or dual SIP session that the devices 12a and 12b communicate. It will be appreciated that in addition to receiving a data packet stream over the primary channel, the receiver module 24b also receives a data packet streams over the communication network 16, or in other words the secondary channel. In this way, increased independent redundancy to the primary channel is provided by the secondary channel. It follows that the receiver module 24b receives two streams as illustrated in Figures 8 to 10.

Now turning to Figure 12 of the drawings, it will be understood that should the receiver module 24b or 34 as the case may be receive data packet streams 71 and 73 with lost or missing data packets, the receiver 24b or 34 passes the received data packet streams 71 and 73 received via the two communication networks 14 and 16 respectively to a jitter buffer 70. The jitter buffer 70 then combines the data packet streams 71 and 73 to reconstruct or produce a combined and complete data packet stream 74. In a preferred embodiment, the server 30 makes use of the error correction module 39 which includes or is communicatively coupled to the jitter buffer to correct errors in data packets received.

The method as described above iterates for as long as the users of the devices 12a and 12b talk.

In an example embodiment where no or little independent redundancy is provided, the bit rate of the primary and secondary channels may be increased resulting in increase audio quality at the receiving device.

The invention as hereinbefore described at least improves or provides acceptable QoS for media, particularly speech, transmission and reception. The invention aims to provide at least dependable asynchronous media transmission on best effort GSM GPRS mobile networks by VANS in unmanaged and uncontrolled wireless network environments. The invention as hereinbefore described provides increased independent redundancy and also increased independent capacity to the primary communications channel. Also, the use of primary and secondary channels simultaneously for communication in a single SIP session provides a way of increasing audio quality, for example audio speech quality at a receiving device.

Claims

1. A method of transmitting data from a communication device in a communication system, the method comprising simultaneously transmitting data from the communication device over at least two independent communication networks in parallel, the at least two independent communication networks being operated by at least two independent communication network operators respectively.

2. A method as claimed in claim 1 , the method comprising:

packetizing the data to be transmitted into data packets; and

3. A method as claimed in claim 2, the method comprising:

monitoring the at least two independent communication networks for the independent communication network with the best Quality of Service (QoS);

using the independent communication network with the best QoS as a primary channel for transmission of data packets; and

using the other independent communication network as a secondary channel for parallel transmission of data packets.

4. A method as claimed in claim 3, the method comprising selecting the independent communication network with one or a combination of lowest packet loss, best signal strength or lowest latency as the independent communication network with the best QoS.

5. A method as claimed in either claim 3 or claim 4, the method comprising using the secondary channel at least to provide partial or full independent redundancy or increased independent capacity, or a combination thereof, to the primary channel.

6. A method as claimed in any one of claims 3 to 5, the method comprising using data packets sent on the secondary channel to provide increased independent redundancy to the primary channel.

7. A method as claimed in claim 6, wherein the increased independent redundancy from the secondary channel is used for reconstruction of lost data packets or error correction of data packets from the primary channel.

8. A method as claimed in any one of claims 3 to 7, wherein the primary channel is used for partial redundancy.

9. A method as claimed in any one of the preceding claims, the method comprising:

initiating a single data communication session over the at least two independent telecommunication networks;

transmitting signals over the primary channel, secondary channel or both primary and secondary channel respectively and;

transmitting the data in parallel from the communication device in the single data communication session over the respective independent communication networks.

10. A method as claimed in any one of the preceding claims, the method comprising:

processing data to be transmitted into frames;

encoding each frame; and transmitting the encoded frames in parallel over the at least two independent communication networks as data packet streams.

11. A method as claimed in any one of claims 8 to 10, the method comprising:

transmitting the data packet streams in parallel over the primary and secondary channels in the single data communication session.

12. A method as claimed in any one of claims 3 to 11 , the method comprising transmitting most important bits of the data packet streams over the secondary channel at a reduced bit rate.

13. A method as claimed in any one of the preceding claims, wherein the at least two independent communication networks are independent wireless or mobile telecommunication networks, fixed telecommunication networks, or a combination of a wireless of mobile telecommunication network and a fixed telecommunication network respectively.

14. A method as claimed in any one of claims 9 to 13, wherein the data communication comprises one or a combination of a Session Initiation Protocol (SIP) session, and other data sessions.

15. A method of receiving data in a communication system, the method comprising:

16. A method as claimed in claim 15, the method comprising using data received via the secondary channel to increase independently redundancy to the primary channel.

17. A method as claimed in either claim 15 or 16, the method comprising receiving data in the form of data packets in any configuration, setting, format or scheme on the secondary channel so as at least to increase redundancy.

18. A method as claimed in claim 17, the method comprising reconstructing lost data packets from both the primary and secondary channels.

19. A method as claimed in any one of claims 15 to 18, the method comprising using the secondary channel to provide additional capacity to the primary channel, the additional capacity being used at least for other data transmissions.

20. A method as claimed in any one of claims 15 to 19, wherein the at least two independent communication networks are independent wireless or mobile telecommunication networks, fixed telecommunication networks, or a combination of a wireless of mobile telecommunication network and a fixed telecommunication network respectively.

21. A method as claimed in any one of claims 15 to 20, wherein the communication session comprises one or a combination of a Session Initiation Protocol (SIP) session, and other data sessions. -

22. A communication device comprising:

23. A communication device as claimed in claim 22, the communication device further comprising:

24. A communication device as claimed in either claim 22 or claim 23, wherein the communication device is arranged to establish a single communication session over the primary channel, secondary channel, or both primary and secondary channels.

25. A communication device as claimed in claim 24, wherein the communication session comprises one or a combination of a Session Initiation Protocol (SIP) session, and other data sessions.

26. A communication device as claimed in any one of claims 22 to 25, wherein the transmission module is configured to transmit redundant data on the secondary channel.

27. A communication device as claimed in any one of claims 23 to 26, wherein the receiver module is arranged to use data received from the secondary channel to increase independently redundancy to the primary channel.

28. A communication device as claimed in any one of claims 23 to 27, wherein the transmission module and the receiver module are configured to transmit and receive data comprising data packets in any configuration, setting, format or scheme respectively.

29. A communication device as claimed in any one of claims 23 to 28, wherein the receiver module is arranged to use the secondary channel at least to provide additional capacity to the primary channel.

30. An apparatus operable to initiate or facilitate a single data communication session between at least two communications devices or terminals, the apparatus comprising:

31. An apparatus as claimed in claim 30, wherein the transmission and receiver modules are configured for error correction or reconstruction of lost data from both the primary and secondary channels prior to any further transmission on the primary and secondary channels.

32. An apparatus as claimed in either claim 31 or claim 32, wherein the data transmitted and received by the transmission module and receiver module respectively comprises data packets.

33. A method substantially as herein described with reference to the accompanying drawings.

34. A communication device substantially as herein described with reference to the accompanying drawings.

35. An apparatus substantially as herein described with reference to the accompanying drawings.