Optimization of transmission parameters of a wireless interface based on codec type

362 870 T3 description

Optimization of transmission parameters of a wireless interface based on the codec type. Technical field

The present invention relates, in general, to wireless communication systems and, in particular, to the optimization of a wireless interface within said communication systems based on the type of communication.

Foundation of the invention

Wireless communication systems are well known in the art. In traditional wireless communication systems, real-time services are typically implemented through the use of a circuit-switched infrastructure in conjunction with at least one dedicated wireless resource. A current trend in the industry, however, is the use of so-called packet exchange infrastructures in support of wireless communication systems. In particular, the use of the Internet Protocol (IP) is likely to become an industry standard.

While packet exchange technology is expected to be capable of supporting real-time services such as audio and / or video communications, a fundamental design limitation on any such system will be the efficiency of the wireless (or air) interface. . For these purposes, it has been widely understood that the general additional exchange used in packet exchange technology cannot be transmitted over a wireless interface. To improve efficiency, the headers can either be removed all together or compressed when data presented in a packet exchange format wants to be transmitted over the air. Additionally, it is well known in the art that different types of source encoders produce encoded information having varying levels of error resistance. As a result, certain portions of an encoder output can be less rigorously error-protected than other portions, thereby providing an opportunity to improve the overall efficiency of the wireless interface.

In today's communication systems, the wireless service subscriber or communication units typically communicate with a radio or wireless access network (RAN) which in turn communicates with a packet-switched network that is part of the infrastructure. Often the target of the communications unit is a client coupled to the packet network typically via an intermediate packet exchanged network such as the Internet or the World Wide Web. In order to take advantage of the opportunities described above to optimize the wireless interface, the radio access network needs to have knowledge of the particular type of data transmitted and received for a given communication. In this way, the radio access network will know how to better optimize the wireless interface with the wireless communication units. However, in current systems, the radio access network does not have such knowledge since it is indistinctly "scrambled" in operation. In order to maintain maximum flexibility and still obtain the advantages of the optimized air interface, it would be advantageous to provide a technique for informing the radio access network of the communication types for separate wireless communications between the communication units and infrastructure.

WO / 0215627 A1 describes a communication method and system comprising a first network element, eg a portable terminal, capable of being connected to a second network element. One of the eligible modes is used for communication. A network element is adapted to perform a mode selection procedure, to select the same mode for bidirectional communication between the network elements.

WO / 9916266 A2 describes an arrangement in which applications running on a mobile station or an external network entity such as an Internet service provider can specify on an individual application flow basis a requested quality of service.

In accordance with the present invention, there is provided a method, computer readable medium and apparatus, as defined in the claims. Brief description of the figures

Fig. 1 is a block diagram of a wireless communication system in accordance with the present invention.

Fig. 2 is a flow chart illustrating the operation of a wireless communication system in accordance with one embodiment of the present invention.

Fig. 3 is a block diagram of a wireless communication system based on the so-called Universal Mobile Telecommunications System and in accordance with the present invention.

Figs. 4-6 are illustrations of protocol packages and frame formats according to the prior art.

FIG. 7 is an illustration of an exemplary protocol package in accordance with the present invention.

FIG. 8 is an illustration of an exemplary frame format in accordance with the present invention.

Detailed description of the invention

The present invention relates to a technique for informing a radio access network regarding the type of communication between a communication unit and a network-based client. Based on this information, the radio access network can optimize the wireless interface between the radio access network and the communication unit. For these purposes, any end point of a communication can inform the radio access network of the type of communication. In a presently preferred embodiment, the reporting endpoint may comprise the communication unit itself or the client. Alternatively, the reporting endpoint may comprise a proxy acting on behalf of the communications unit or a call server acting on behalf of the client. Additionally, the type of communication can be configured by information regarding a source encoder to be used during the communication. Preferably, the optimization of the wireless interface may be implemented through the selection of an optimal error correction scheme or through the compression and decompression of headers associated with a plurality of packet exchanged portions.

ES 2 362 870 T3 that constitute the communication. A network element arranged within the radio access network is used to optimize the wireless interface based on the type of communication.

The present invention can be more easily described with reference to Figs. 1-8 that follow. Referring now to FIG. 1, a wireless communication system 100 is illustrated. In particular, the wireless communication system 100 comprises a plurality of mobile communication units or subscribers 102 in wireless communication with a radio access network. 104. Radio access network 104, in turn, is coupled to a packet-switched network 106, which in turn is coupled to an Internet Protocol (IP) -based network 108. A plurality of clients 110 are coupled to the IP network 108. The radio access network 104 may optionally be coupled to a circuit-swapped network 116 as shown.

Communication units 102 preferably comprise mobile or portable devices (such as handheld or in-car radios or radio telephones) capable of communicating with radio access network 104 via one or more wireless channels 112. Preferably, wireless channels 112 comprise one or more radio frequency (RF) channels that implement any of a variety of known protocols and access schemes, such as multiple code division access (CDMA), multiple frequency division access ( FDMA) or multiple time slot accesses (TDMA). As described in greater detail with reference to Fig. 3, the radio access network 104 comprises those elements of an infrastructure that manages wireless communications with the communication units. As shown schematically in FIG. 1, the radio access network 104 comprises one or more network elements 114 that contribute to the operation of the radio access network. In relation to the communication units 102, the radio access network 104 implements a wireless interface through the wireless channels 112 by which the communication units 102 are able to communicate with the radio access network 104, as well as the various IP and packet exchange networks illustrated in Fig. 1.

Although the packet exchange network 106 is described in greater detail with reference to FIG. 3 below, it is characterized by the use of headers to effect routing of data throughout the entire packet network. As is known in the art, such packet exchange networks provide efficient use of available resources relative to traditional circuit exchange networks because the resources are not applied to particular communications for the duration of those communications. Similarly, the IP network 108 is a packet-based network of a type commonly used on the Internet and the World Wide Web. Thus, clients 110 can comprise computer devices capable of terminating the IP protocol, as is known in the art.

When a communication unit 102 engages in communication with a client 110, both the communication unit and the client can be considered an end point for communication. In traditional first and second generation communication systems, the encoder / decoder (codec) devices were generally barely encoded within the communication ends. For example, in many land mobile radio communication systems voice compression codecs are used to maximize the spectral efficiency of voice data transmitted over a wireless interface. In these systems, since a single voice codec is provided, the wireless interface between the communication units and the radio access network is strictly optimized for that type of individual source codec. However, with the advent of real-time services, such as Voice over IP (VoIP), any of a variety of encoders can be used for a given communication. Thus, the wireless interface provided by the radio access network cannot be optimized for the source encoder chosen for a particular communication.

To this end, the present invention provides a technique for informing the radio access network of a communication type for a given communication such that the radio access network can subsequently optimize the wireless interface. Referring now to Fig. 2, a flow chart illustrating a process in accordance with the present invention is illustrated. Preferably, the process illustrated in Fig. 2 It is implemented through the use of stored computer executable instructions that are executed by an appropriate processor within an appropriate platform or platforms. Such implementation techniques are well known in the art. Thus, at block 202, an end point for a communication determines a communication type for the communication. In general, the type of communication can comprise any information sufficient to allow a network element to determine how to optimize the wireless interface. In a presently preferred embodiment, the type of communication is indicated through a type of source encoder that will be used during communication. Typically, the type of source encoder to be used during communication is determined by the type of services and is explicitly (or implicitly) requested during call setup. For example, for voice-only communication with a particular class of communication units, a certain voice coder may be used, eg, a full-rate GSM codec in GSM networks. In contrast, where the communication comprises only video data, an appropriate video encoder may be used, eg, H.263 or MPEG 2.0 codecs. It is possible that a combination of multiple encoders may be used as in the case of a communication comprising voice and video data. It is even possible to change the chosen source encoder during a call. Notwithstanding the foregoing, the present invention is capable of managing each of these scenarios. It should be noted that the endpoints may also comprise a number of entities acting on behalf of the communication units or clients. As further described with reference to Fig. 3 below, devices such as a wireless proxy and call server can be used on behalf of the communication unit and / or the client.

Notwithstanding the foregoing, in block 204 the endpoint that has determined the type of communication for the communication informs the access network

ES 2 362 870 T3 by radio of this type of communication. This can be achieved through the use of either an explicit or an implicit messaging scheme. In the case of an explicit messaging scheme, a new message is created, or existing messages are modified to include information indicating the type of communication to the radio access network, e.g., via the radio access network. incorporation of an additional protocol phase or improvement of the existing protocol phase. Thus, for example, where the communications unit is the endpoint that informs the radio access network of the type of communication, a new message can be created within a protocol used by the communications unit to communicate with the network. radio access network, the message of which includes the information related to the type of communication. It should be noted that, in some situations, the communication unit essentially acts as a wireless modem for a device attached to the communication unit, which device is the actual end point for communication. In this case, the communication unit receives the communication type information from the attached device as needed. Alternatively, where the client, or a call server acting on behalf of the client, acts as the endpoint informing the radio access network of the type of communication, an explicit message defined within the appropriate protocol may be added between the client (or call server) and radio access network (or agent on their behalf). As described in greater detail below in relation to Fig. 3, the packet exchange network 106 may comprise a wireless agent acting on behalf of the radio access network 104, whose agent is designated to receive said explicit message from the call client or server and subsequently inform the access network radio communication type.

In an alternative embodiment, instead of an explicit message sent by the endpoint to the radio access network, said indication is implicitly included in the information sent to the radio access network through an endpoint. . A particular example of this alternative is described below with reference to Figs. 4-8. In general, such implicit methods are characterized by the presence of sufficient information within each data packet to indicate the appropriate techniques that will be used to optimize the wireless interface.

Once the radio access network has been informed of the type of communication, it can, at block 206, optimize the wireless interface between the radio access network and the particular communication unit involved in that communication based on the type of communication. communication information. In a presently preferred embodiment, said optimization is achieved through either or both of two schemes. In the first, an optimal error correction scheme is chosen for the wireless interface based on the type of communication. As is known in the art, the data output performed by certain source encoders has varying degrees of susceptibility to errors induced during data transmission. For example, it is well known that certain speech codecs provide output parameters that are relatively insensitive to channel errors while other endpoints are highly sensitive to channel errors. In order to maximize spectral efficiency when transmitting these parameters over a wireless interface, it is therefore known how to provide a higher degree of error protection for those bits that have a higher degree of sensitivity to channel errors, while those Parameters that have relatively negligible susceptibility to channel errors are protected to a lesser degree or left unprotected altogether. Since this type of selective error coding is dependent on the source encoder used, the present invention allows the radio access network to select an optimized error coding scheme based on its knowledge of the type of communication. Such knowledge may be predetermined, in which case the radio access network knows how to apply a predetermined error correction scheme based on the type of communication provided by one of the endpoints. In a more generalized scheme, however, the radio access network can become aware of only varying levels of error protection that it is free to apply to the data as needed. The appropriate level of error protection is therefore based only on the knowledge of the different amounts of parameters within a given package that will be provided within each error sensitivity class. Some specific examples of the concepts described above in relation to Fig. 2 are further described with reference to Figs.

3-8.

In the second optimization scheme, packet header compression / decompression is used. Such techniques are well known in the art, and include compression of the Van Jocobsen header. Alternatively, again using known techniques, the headers can be discarded together on the sending side and reconstructed on the receiving side of a communication. Header discard and reconstruction is further described in copending US Patent Application Serial No. 09 / 887,831. Notwithstanding the foregoing, compression / decompression or removal / reconstruction techniques minimize the amount of data that will be sent through the wireless interface, thereby improving throughput and bandwidth usage efficiency.

Referring now to Fig. 3, a wireless communication system 300 based on a Universal Mobile Telecommunications System (UMTS) model is illustrated. Wireless communication system 300 comprises base station systems 302, 308, radio network subsystems 304, 306, and a core network 310. The core network 310 can be coupled to an IP network 312 and the IP network 312, in turn, can be coupled to one or more clients 314 and one or more call servers 316. A plurality of communication units 328 can communicate with base station systems 302, 308 and / or radio network subsystems 304,306. Each of the elements illustrated in Fig. 3 are well known in the art and have been functionally defined. Additionally, for the purposes of the present invention, each of the elements illustrated in Fig. 3 comprises processors and storage devices suitable for implementing software algorithms as is known in the art.

ES 2 362 870 T3

As shown, each base station system 302, 308 comprises a base station controller 320 coupled to one or more base transceiver systems 322. As is known in the art, the base station controller 320 controls the operation of base transceiver systems 322 which, in turn, comprise one or more wireless transceivers used to implement a wireless interface in accordance with the present invention. In a similar branch, each radio network subsystem 304, 306 comprises a radio network controller 324 coupled to one or more nodes 326. Each node 326 is essentially a logical representation of the equipment responsible for wireless transmission and reception within one or more coverage areas. In turn, the radio network controller 324 controls the use and integrity of the available wireless resources represented by the corresponding nodes.

The core network 310 preferably comprises a packet swap (PS) portion illustrated on the right and a circuit swap (CS) portion illustrated on the right. As shown in FIG. 3, a base station system 302, 308 may be coupled to either the packet swap portion of the core network 310, or the circuit-switched portion of the core network 310. Rather, each radio network subsystem 304, 306 may be coupled to both the packet swap portion and the loop-swap portion of the core network 310. As is known in the art, the swap-per-pack portion Core network packet 310 typically comprises a plurality of support nodes. In particular, as shown in Fig. 3, a service support node 330 (SGSN) is provided and coupled to a portal support node (GGSN) 332. The sGsn stores subscription information and location information necessary to implement the packet exchange services for each communication unit registered with that SGSN. The GGSN 332 stores subscription information and addressing information necessary to address the data traffic of the packet received from the IP network 312 and destined for one of the communication units 328. In the circuit-switched portion of the core network 310, a mobile exchange center 334 performs functions to handle circuit-exchange services to and from communication units 328. It should be noted that the present invention has no effect on, nor is it It is affected by the operation of the circuit-switched portion of the core network.

In the context of the present invention, base station systems 302, 308 or radio network sub-systems 304, 306 constitute the radio access network portion of system 300. Additionally, the base station controller 320 and base transceiver systems 322, or the radio network controllers 324 and nodes 326 comprise appropriate network elements to implement the functionality attributed to the radio access network as described. in relation to Fig. 2. In addition, the SGSN 330 can serve as a wireless agent acting on behalf of the radio access network. As previously described, by using an explicit messaging scheme, an endpoint such as a communications unit

328 or wireless proxy 336, 318 acting on behalf of the communication unit 328, can send an indication of the type of communication directly to the base station system 302, 308 or radio network subsystem 304,306. Alternatively, a client 314 or call server 316 acting on behalf of client 314, can send an explicit message to the server support node 330 on behalf of the appropriate base station system 302, 308 or radio network subsystem 304, 306. As illustrated in FIG. 3, wireless proxy 336 may be coupled to SGSN 330 or IP network 312. In a typical call server and wireless proxy application, a communications unit will communicate with the wireless proxy in an effort to establish communications with a particular client. The wireless proxy from here will communicate with a call server, acting on behalf of the client, to establish communication. Once communication has been established by the wireless proxy and call server, the communication unit and the client can take over the communication. Regardless of the mechanism used to establish communications between a communications unit and the client, an implicit or explicit message scheme can be used to inform the RAN, as mentioned above. An example of an implicit messaging scheme based on modifications to existing protocols is further illustrated with respect to Figs.

4-8.

Referring now to Fig. 4, a protocol package according to the prior art is illustrated. The illustrations in Figs. 4, 5 and 7 are based on the concept of the Open Systems Interconnection (OSI) Model in which each phase of the protocol uses the phase immediately below it and provides services for the phase immediately above it. The protocol package shown in Fig. 4 it could be exchanged between a codec, normally located within the core network, and a radio network controller, and thus forms a part of the so-called UI interface. A codec protocol 402 comprising data frames generated by a codec occupies the highest level in the protocol package. In practice, the codec protocol 402 is passed transparently through the radio network controller and terminated with a codec within a communications unit. A frame protocol 404 produces data packets in accordance with a frame format and supports communication between the codec within the core network and the radio network controller. The lower phases of the protocol 406, 408, corresponding to the data link phase and the physical phase, respectively, as designated in the OSI model, are provided as is known in the art.

On the other side of the packet exchange portion of the core network, that is, from core network 310 to IP network 312 through GGSN 332, a protocol package such as the one illustrated in Fig. 5. As indicated above, a 502 codec protocol occupies the highest level in the protocol suite. In this case, the codec protocol 502 constitutes data frames originated by a codec within a communications unit and terminated by a client residing on the network with packet exchange. The frames generated by the codec are encapsulated by a protocol phase5

ES 2 362 870 T3 real-time (RTP) / User Datagram Protocol (UDP) / IP 504 encapsulation. RTP / UDP / IP encapsulation allows data to be properly routed when transmitted over the network. IP. As in Fig. 4, the lower protocol phases 506, 508 are again provided as needed.

A codec frame format typical of the prior art is further illustrated with reference to Fig. 6. In particular, the frame format shown in Fig. 6 is typical of those found in traditional circuitry. with exchange for circuits. For the purposes of the present invention, the frame format in Fig. 6 illustrates the concept of sub-streams corresponding to a given communication. In this case, a user plane protocol header 602 that is part of the Iu Interface designates which communication a particular set of sub-flows 604-608 belongs to, that is, which communication unit has established this communication. Each sub-stream preferably corresponds to a different level of susceptibility to error and, consequently, to a different level of protection required against errors. For example, in a Multi-Adaptive Rate (AMR) codec used to encode speech, there are three different phases of error protection. The concept of sub-streams is exploited by the present invention as a means of providing an implicit indication of the type of communications to a radio access network.

Referring now to FIG. 7, a protocol package in accordance with the present invention is illustrated. In particular, like the protocol package illustrated in Fig. 5, the protocol package of Fig. 7 supports communication between a core network and an IP network. In this way, a codec protocol layer 702 is encapsulated again in the RTP / UDP / IP header information through the RTP / UDP / IP phase 704. However, a so-called enhanced frame protocol phase 706 is interposed between the RTP / UDP / IP phase 704 and the lower phases 708, 710. The enhanced frame protocol phase 706, further illustrated in Fig. 8 , communicates, on a packet-by-packet basis, information specific to the RTP / UDP / IP 802 encapsulation as an additional sub-stream relative to the frame format. Additionally included are sub-stream descriptors 804808 illustrative of the nature of the data included in each sub-stream that is part of the codec 702 protocol. With this knowledge, the radio access network, after By receiving the enhanced frame protocol phase, you can optimize the error correction for the data transmitted over the wireless interface. In this way, the radio access network can be notified of the type of communication and thus optimize the wireless interface. It should be noted that the scheme illustrated in Figs. 7 and 8, as those skilled in the art will recognize, is only one of many implementations of the implicit messaging scheme in accordance with the present invention, and is provided by way of example rather than limitation.

The present invention refers to a technique by which the end points of a communication, or other entities on their behalf, inform a radio access network regarding the type of communication between the end points, which allows this so that the radio access network optimizes a wireless interface. In contrast to prior art systems, this allows for greater flexibility regarding the types of services that can be offered, while ensuring that such service will be supported on the wireless interface in an optimal way.

In the foregoing specification, the invention has been described with reference to specific embodiments. However, a person skilled in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as indicated in the claims that follow. As a consequence, the specification and figures should be construed as illustrative rather than in a restrictive sense.

The benefits, other advantages, and solutions to the problems have been described with respect to specific embodiments. However, benefits, advantages, solutions to problems, and any element (s) that may cause any benefit, advantage, or solution to occur or become more pronounced, should not be construed as critical, required, or essential features or elements. of none or all claims. As used herein, the terms "comprises", "comprising" or any variation of the foregoing, is intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus comprising a list of items It does not include only those elements but may include other elements not expressly mentioned or inherent in said processes, method, article or apparatus.