WO2009036698A1

WO2009036698A1 - A method, a system and a device for data transmission

Info

Publication number: WO2009036698A1
Application number: PCT/CN2008/072377
Authority: WO
Inventors: Guohong Li; Jiang GUO; Ming Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-17
Filing date: 2008-09-17
Publication date: 2009-03-26
Also published as: CN101394584A; CN102769609B; CN101394584B; CN102769609A

Abstract

A GSM network is disclosed. Said GSM network comprises TDM BS, IP BS, BSC and MSC; Said TDM BS and said IP BS communicate with said MSC through said BSC; said BSC is used to perform the data format transform and/or protocol transition for the service data among said TDM BS, said IP BS and said MSC. A base station controller, a base station subsystem and a data transmission method are also disclosed. In said GSM network, BSC is connected to IP BS and TDM BS at the same time. By employing BSC to perform the data format transform and/or protocol transition for the service data among TDM BS, IP BS and MSC, there is no need to use an external device to perform the transform between IP and TDM, and MSC is able to communicate with TDM BS and IP BS when A-interface is using IP.

Description

Method, system and device for data transmission

This application claims priority to Chinese Patent Application No. 200710151245.4, entitled "Method, System and Apparatus for Data Transmission", filed on September 17, 2007, the entire contents of which are incorporated by reference. In this application. Technical field

Embodiments of the present invention relate to the field of wireless communications technologies, and in particular, to a data transmission method, system, and apparatus. Background technique

With the rapid development of wireless communication technologies, the GSM (Global System Mobile) network has been widely used. Now the GSM network generally uses the structure shown in Figure 1. The GSM network consists of two subsystems: BSS (Base Station sub-System) and NSS (Network Sub System). The BSS provides mobile stations. The access and management functions of the wireless interface, NSS provides mobility management, security management, voice exchange and construction of various voice service functions on the voice channel exchange for the GSM system (basic voice call function, voice with supplementary services) Call function, etc.). The BSS includes multiple BTSs (Base Transceiver Stations, which can be referred to as base stations) (only two BTSs are shown in Figure 1: BTS11 and BTS12, and the remaining BTSs are not marked), BSC13 (Base Station Controller, Base Station) Controller) and TC14 (TransCoder, code converter); NSS includes MSC15 (Mobile Switching Center, Mobile Switching Center) and 110 16 (Home Location Register). BSC13 and BTS are connected by Abis interface; 88 3 and 14 are connected by ^61" interface, TC14 is controlled by BSC13, and is implemented by Ge manufacturer; TC14 and MSC15 are connected by A interface; HLR16 is connected to MSC 15 .

In the existing GSM network, the external interface provided by the BSS is a TDM (Time Division Multiplexing) circuit interface: the A interface provides 64 Kbps. TDM circuit interface, Abis interface provides 16/8 Kbps TDM circuit interface. The BSS is connected to the NSS through a 64Kbps TDM circuit, and the BSC is connected to the BTS through a 16/8 Kbps TDM circuit. The interface switching capability of the A interface is limited. The codec format that can be processed by this interface is only PCM (Pulse Code Modulation) (there are two variants of A-law and μ-law depending on the country and region). Regardless of the codec format used by the user terminal, the BSC must be converted to the PCM format before being sent to the NSS for processing. The Abis interface carries the air interface voice coding in a TRU circuit of 16/8 Kbps in the format of a Transcoder and Rate Adapter Unit (TRAU). Therefore, in the existing GSM network, the BSS must support the TRAU function. After completing the above codec conversion function, the PCM code stream is placed in the TDM circuit and then sent to the NSS for processing.

In carrying out the invention, the inventors have found that at least the following problems exist in the prior art:

The base station under a BSC management has a large geographical distribution. As the transmission network evolves, the base station is required to gradually use IP transmission. When some base stations use TDM transmission, and another part of the base stations use IP transmission, the base station using IP transmission The conversion between IP and TDM must be performed through an external device to achieve IP transmission of base station data, poor networking flexibility, and reduced network reliability. Summary of the invention

Embodiments of the present invention provide a data transmission method, system, and apparatus, which can complete data transmission between a BSC and an IP base station and a TDM base station without performing an IP and TDM conversion by an external device.

To achieve the above objective, the technical solution of an embodiment of the present invention provides a GSM network, including: a TDM base station, an IP base station, a BSC, and an MSC; the TDM base station, the IP base station, and the MSC by using the BSC The BSC is configured to perform data format conversion and/or protocol conversion on the service data between the TDM base station, the IP base station, and the MSC. The technical solution of an embodiment of the present invention further provides a base station controller, including

Abis interface TDM data processing unit, Abis interface IP data processing unit, format conversion and protocol conversion unit and A interface IP data processing unit; said Abis interface TDM data processing unit, for said TDM base station and said format conversion and protocol Data transmission between the conversion units; the Abis interface IP data processing unit, configured for data transmission between the IP base station and the format conversion and protocol conversion unit; the A interface IP data processing unit and Data transmission between the MSC and the format conversion and protocol conversion unit; the format conversion and protocol conversion unit, configured to the Abis interface TDM data processing unit, the Abis interface IP data processing unit, and the The service data between the A interface IP data processing units performs data format conversion and/or protocol conversion.

A technical solution of an embodiment of the present invention further provides a base station subsystem, including a TDM base station, an IP base station, and a BSC;

The BSC includes an Abis interface TDM data processing unit, an Abis interface IP data processing unit, a format conversion and protocol conversion unit, and an A interface IP data processing unit; the Abis interface TDM data processing unit, the TDM base station and the Data transfer between format conversion and protocol conversion unit;

The Abis interface IP data processing unit is configured to perform data transmission between the IP base station and the format conversion and protocol conversion unit;

The A interface IP data processing unit is configured to perform data transmission between the MSC and the format conversion and protocol conversion unit;

The format conversion and protocol conversion unit is configured to perform data format conversion on the service data between the Abis interface TDM data processing unit, the Abis interface IP data processing unit, and the A interface IP data processing unit. Or the conversion of the agreement.

The technical solution of an embodiment of the present invention further provides a data transmission method, including the following steps: receiving service data of a source device; and if the destination device of the service data is a TDM base station, converting the service data to Abis The TDM encapsulation of the interface; or, if the destination device of the service data is an IP base station, converting the service data into an IP encapsulation of the Abis interface; or, if the destination device of the service data is The MSC converts the service data into an IP encapsulation of the A interface, and sends the converted service data to the destination device.

The technical solution of an embodiment of the present invention further provides a data transmission method, including the following steps: receiving service data of a source device; and if the destination device of the service data is an IP base station, converting the service data to Abis The IP encapsulation of the interface; or, if the destination device of the service data is an MSC, convert the service data into an IP encapsulation of the A interface; or send the converted service data to the destination device.

The technical solution of the embodiment of the present invention has at least the following advantages: In the embodiment of the present invention, the BSC simultaneously connects the IP base station and the TDM base station, and performs data format conversion and/or data transmission data service data between the TDM base station, the IP base station, and the MSC. The conversion of the protocol enables communication between the MSC and the TDM base station and the IP base station when the A interface is IP-free without the need to convert the IP and TDM through the external device. DRAWINGS

1 is a structural diagram of a prior art GSM network;

2 is a structural diagram of a GSM network according to an embodiment of the present invention;

3 is a structural diagram of an A-interface signaling plane protocol stack according to an embodiment of the present invention; FIG. 4 is a structural diagram of an A-interface bearer plane protocol stack according to an embodiment of the present invention; A structural diagram of an Abis interface bearer plane protocol stack; FIG. 6 is a flowchart of a data transmission method according to an embodiment of the present invention. detailed description

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

The structure of a GSM network according to an embodiment of the present invention is as shown in FIG. 2, and includes a TDM base station 21, an IP base station 22, a BSC 23, and an MSC 24. The BSC 23 is respectively connected to the TDM base station 21 and the IP base station 22 through an Abis interface, and the BSC 23 passes through the A interface and MSC24 connection. The TDM base station 21, the IP base station 22, and the BSC 23 constitute a BSS, and the BSS Connected to the MSC24 via the A interface. The MSC in the embodiment of the present invention may include an MSC Server and an MGW (Media Gateway).

The BSC 23 is used for data format conversion and/or protocol conversion of service data between the TDM base station 21, the IP base station 22, and the MSC 24. The BSC 23 includes an Abis interface TDM data processing unit 231, an Abis interface IP data processing unit 232, a format conversion and protocol conversion unit 233, and an A interface IP data processing unit 234; wherein the Abis interface TDM data processing unit 231 and the TDM base station 21 and format conversion, respectively Connected to the protocol conversion unit 233, the Abis interface IP data processing unit 232 is connected to the IP base station 22 and the format conversion and protocol conversion unit 233, respectively, and the A interface IP data processing unit 234 is connected to the MSC 24 and the format conversion and protocol conversion unit 233, respectively.

The Abis interface TDM data processing unit 231 is used for data transmission between the TDM base station 21 and the format conversion and protocol conversion unit 233; the Abis interface IP data processing unit 232 is used between the IP base station 22 and the format conversion and protocol conversion unit 233. Data transmission; A-interface IP data processing unit 234 for data transmission between MSC 24 and format conversion and protocol conversion unit 233.

The format conversion and protocol conversion unit 233 is configured to perform data format conversion and/or protocol conversion on the service data between the Abis interface TDM data processing unit 231, the Abis interface IP data processing unit 232, and the A interface IP data processing unit 234. The conversion of the service data protocol refers to converting the service data from the original protocol package to the destination protocol package. For example, the service data processed by the Abis interface TDM data processing unit 231 may be data encapsulated by the TRAU/TDM protocol, and the A interface IP data. The service data processed by the processing unit 234 may be data encapsulated by RTP/UDP/IP; a protocol for converting the protocol of the service data of the Abis interface TDM data processing unit 231 into the service data of the A interface IP data processing unit 234, which may specifically be : The data encapsulated by the TRU/TDM protocol sent by the Abis interface TDM data processing unit 231 is converted into data encapsulated by RTP/UDP/IP.

The format conversion and protocol conversion unit 233 includes a format conversion subunit 2331, an Abis interface TDM data and an A interface IP data protocol conversion subunit 2332, an Abis interface TDM data, and an Abis interface IP data protocol conversion subunit 2333 and an Abis interface IP data and The A interface IP data protocol conversion subunit 2334; wherein the format conversion subunit 2331 is connected to the Abis interface TDM data processing unit 231 and the A interface IP data processing unit 234, respectively, and the Abis interface TDM data and the A interface IP data protocol conversion subunit 2332 respectively Connected to the Abis interface TDM data processing unit 231 and the A interface IP data processing unit 234, the Abis interface TDM data and the Abis interface IP data protocol conversion subunit 2333 are respectively connected to the Abis interface TDM data processing unit 231 and the Abis interface IP data processing unit 232. The Abis interface IP data and the A interface IP data protocol conversion subunit 2334 are connected to the Abis interface IP data processing unit 232 and the A interface IP data processing unit 234, respectively.

The format conversion sub-unit 2331 is configured to compress the idle voice frame of the service data of the Abis interface TDM data processing unit 231 in the uplink direction, and recover the idle voice frame of the service data of the A interface IP data processing unit 234 in the downlink direction; The interface TDM data and the A interface IP data protocol conversion subunit 2332 are configured to convert the protocol of the service data of the Abis interface TDM data processing unit 231 into the service data of the A interface IP data processing unit 234 in the uplink direction, in the downlink direction. A protocol for converting the protocol of the service data of the A interface IP data processing unit 234 into the service data of the Abis interface TDM data processing unit 231; Abis interface TDM data for switching between the occurrence of the TDM base station and the IP base station, in Abis Protocol conversion between the service data protocol of the interface TDM data processing unit 231 and the service data protocol of the Abis interface IP data processing unit 232; Abis interface IP data, for the service data of the Abis interface IP data processing unit 232 in the uplink direction The protocol is converted to the A interface IP data processing unit 234 The service data protocol converts the protocol of the service data of the A-interface IP data processing unit 234 into the protocol of the service data of the Abis interface IP data processing unit 232 in the downstream direction. The protocol of the service data of the Abis interface TDM data processing unit 231 may include a TRAU/TDM protocol, and the protocol of the service data of the Abis interface IP data processing unit 232 may include a UDP (User Datagram Protocol)/IP protocol. The protocol of the service data of the A interface IP data processing unit 234 may include an RTP (Real Time Transfer Protocol) / UDP/IP protocol.

BSC23 is connected to MSC24 through A interface. When A interface is IP, A The structure of the interface signaling plane protocol stack can be as shown in Figure 3. The A interface signaling protocol is carried in

On the SIGTRAN (Signaling Transport Protocol)/SCTP (Stream Control Transmission Protocol), the M3UA (MTP3-User Adaptation Layer) protocol is used for bearer. The SIGTRAN protocol is a set of transmission control protocols for transmitting signaling over IP networks. SIGTRAN defines a relatively complete SIGTRAN protocol stack, which is divided into four layers: IP protocol, signaling transmission, signaling transmission adaptation and signaling application. The SCTP protocol is a connection-oriented transport layer protocol. It uses TCP-like traffic control and congestion control algorithms to ensure reliable transmission of user data between two SCTP endpoints through its own authentication and retransmission mechanism. The M3UA protocol is an MTP third-level user adaptation layer protocol, which provides signaling point coding and IP address translation, and is used to implement the transmission of the SS7 protocol between the softswitch and the signaling gateway, and supports the transmission of the MTP on the IP network. The third level of user messages.

When the A interface is IP, the structure of the A interface bearer plane protocol stack can be as shown in Figure 4. The GSM compressed voice codec is carried on the RTP/UDP/IP protocol. The core network is responsible for handling all codec-related transactions, including codec negotiation and codec conversion after negotiation failure, and completes the exchange of voice packets.

The BSC 23 is connected to the TDM base station 21 and the IP base station 22 through the Abis interface respectively, and the user plane transmission of the Abis interface connected to the TDM base station 21 can maintain the structure of the prior art, and when the Abis interface is already IPized, the Abis interface bearer plane protocol stack The user plane protocol of the Abis interface connected to the IP base station 22 is carried over the UDP/IP protocol and is carried by the PTRAU protocol.

A method for data transmission according to an embodiment of the present invention is as shown in FIG. 6, and includes the following steps:

Step s601: Receive service data of a source device, where the source device may include a TDM base station, an IP base station, or an MSC.

In step s602, the service data is converted into a protocol. If the destination device of the service data is a TDM base station, the service data is converted into a TDM encapsulation of the Abis interface. If the destination device of the service data is an IP base station, the service data is used. Converted to an IP encapsulation of the Abis interface; if the destination device of the service data is an MSC, the service data is Converted to the IP encapsulation of the A interface. During the conversion process, when the source device is a TDM base station and the destination device is an MSC, the idle voice frame of the service data needs to be compressed, and the compressed service data may further include time information and frame number, and the time information is used for control. Delay, jitter, and time recovery at the endpoint, the frame sequence is used to control packet loss, out of order, and to reduce the delay introduced by debounce, the format transform subunit 2331 can be based on the length of the delay and the amplitude of the jitter. The length of the packet is adaptively adjusted. When the source device is the MSC and the destination device is the TDM base station, the idle voice frame of the service data needs to be restored. The recovery process may be: recording the latest SID frame during the VAD period. Fill with the latest SID frame to recover the idle voice frame of the service data.

Step s603: Send the converted service data to the destination device, where the destination device includes a TDM base station, an IP base station, or an MSC.

When the GSM network shown in Figure 2 is used, the communication process between the base station and the MSC can be as follows:

When the TDM base station 21 transmits data to the MSC 24, the Abis interface TDM data processing unit 231 first receives the data transmitted by the TDM base station 21; then the format conversion subunit 2331 compresses the idle voice frame of the service data, and the compressed service data may include Time information and frame number, time information is used to control delay, jitter and time recovery at the endpoint, frame number is used to control packet loss, out of order, and to reduce delay introduced by debounce, format conversion subunit 2331 The length of the packet can be adaptively adjusted according to the length of the delay and the amplitude of the jitter; and the Abis interface TDM data and the A interface IP data protocol conversion subunit 2332 convert the Abis interface TRAU/TDM protocol of the service data into the A interface RTP. /UDP/IP protocol; finally, the converted data is sent to the MSC 24 through the A interface IP data processing unit 234, and the core network element is responsible for processing all the codec related transactions, which may include codec negotiation and editing after the negotiation fails. Decode the conversion and complete the exchange of voice packets.

When the MSC 24 transmits the data to the TDM base station 21, the A interface IP data processing unit 234 first receives the data transmitted by the MSC 24; then the format conversion subunit 2331 records the latest SID frame during VAD (Voice Activity Detection). Filling with the latest SID frame to recover the idle voice frame of the service data; And the Abis interface TDM data and the A interface IP data protocol conversion subunit 2332 converts the A interface RTP/UDP/IP protocol of the service data into the Abis interface TRAU/TDM protocol; finally, the converted data is processed by the Abis interface TDM data processing unit 231. It is sent to the TDM base station 21.

When the IP base station 22 transmits data to the MSC 24, the Abis interface IP data processing unit 232 first receives the data transmitted by the IP base station 22; then the Abis interface IP data and the A interface IP data protocol conversion subunit 2334 the Abis interface of the service data UDP/ The IP protocol is converted to the A interface RTP/UDP/IP protocol; finally, the converted data is sent to the MSC 24 through the A interface IP data processing unit 234, and the core network element is responsible for processing all the codec related transactions, which may include codec. The codec conversion after negotiation and negotiation fails, and the exchange of voice packets is completed.

When the MSC 24 transmits the data to the IP base station 22, the A interface IP data processing unit 234 first receives the data transmitted by the MSC 24; then the Abis interface IP data and the A interface IP data protocol conversion subunit 2334 associates the A data interface RTP/UDP/ of the service data. The IP protocol is converted to the Abis interface UDP/IP protocol; finally, the converted data is transmitted to the IP base station 22 via the Abis interface IP data processing unit 232.

When the service is switched by the TDM base station 21 to the IP base station 22, the Abis interface TDM data and the Abis interface IP data protocol conversion subunit 2333 are in the service data protocol of the Abis interface TDM data processing unit 231 and the service of the Abis interface IP data processing unit 232. Protocol conversion between data protocols. After the handover is completed, the MSC 24 stops the transmission of the service data with the TDM base station 21, and the MSC 24 and the IP base station 22 perform the transmission of the service data. This conversion process is transparent to the A interface.

When the service is switched by the IP base station 22 to the TDM base station 21, the Abis interface TDM data and the Abis interface IP data protocol conversion subunit 2333 are in the service data protocol of the Abis interface IP data processing unit 232 and the service of the Abis interface TDM data processing unit 231. Protocol conversion between data protocols. After the handover is completed, the MSC 24 stops the transmission of the service data with the IP base station 22, and the MSC 24 and the TDM base station 21 perform the transmission of the service data. This conversion process is transparent to the A interface.

In the embodiment of the present invention, the BSC simultaneously connects the IP base station and the TDM base station, and the pair The data format conversion and/or protocol conversion between the TDM base station, the IP base station and the MSC can realize the MSC and the IP of the A interface without IP and TDM conversion through the external device. Communication between the TDM base station and the IP base station.

Moreover, in the embodiment of the present invention, the BSC always sends the uncoded converted voice signal to the core switching network for processing. When the codec of the two user terminals is the same, the core switching network can directly exchange the voice signal. Avoid unnecessary codec conversion (for example: In the process of implementing the present invention, the inventors have found that at least the following problems exist in the prior art: BSS side channels always have to perform codec conversion before switching, for moving to mobile Calling, even if the same voice codec function is supported between two user terminals, it is always necessary to perform two codec conversions, thereby improving the voice quality.

In addition, since the PCM format is an uncompressed speech codec format, each call voice signal needs to occupy a fixed bandwidth, which is much higher than the compressed voice codec bandwidth, and the IP interface is a statistical multiplexing interface, and the bandwidth utilization rate is high, Granularity limitation, each voice channel uses only the bandwidth and IP header overhead required for compressed speech codec. During the user's silence, voice packets may not be transmitted, and idle voice frame recovery is not required. Therefore, the bandwidth of the embodiment of the present invention is improved. usage efficiency.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or can be implemented by means of software plus necessary general hardware platform, and the technical solution of the present invention can be implemented. Reflected in the form of a software product, the software product can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for making a computer device (may be A personal computer, server, or network device, etc., performs the methods described in various embodiments of the present invention.

In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A global mobile communication system network, comprising:

Time division multiplexing TDM base station, IP base station, base station controller BSC and mobile switching center MSC;

The TDM base station and the IP base station communicate with the MSC through the BSC;

The BSC is configured to perform data format conversion and/or protocol conversion on service data between the TDM base station, the IP base station, and the MSC.

2. The GSM system network according to claim 1, wherein the BSC comprises an Abis interface TDM data processing unit, an Abis interface IP data processing unit, a format conversion and protocol conversion unit, and an A interface IP data processing unit. ;

The Abis interface TDM data processing unit is configured to perform data transmission between the TDM base station and the format conversion and protocol conversion unit;

3. The GSM system network of claim 2, wherein the format conversion and protocol conversion unit comprises:

Abis interface TDM data and A interface IP data protocol conversion subunit, a protocol for converting the protocol of the service data of the Abis interface TDM data processing unit into the service data of the A interface IP data processing unit in the uplink direction, a protocol for converting a protocol of service data of the A interface IP data processing unit into a service data of the Abis interface TDM data processing unit in a downlink direction;

Abis interface IP data and A interface IP data protocol conversion sub-unit for uplink a protocol for converting the protocol of the service data of the Abis interface IP data processing unit into the service data of the A interface IP data processing unit, and converting the protocol of the service data of the A interface IP data processing unit to a protocol in the downlink direction The protocol of the service data of the Abis interface IP data processing unit.

The global mobile communication system network according to claim 3, wherein the format conversion and protocol conversion unit further comprises:

Abis interface TDM data and Abis interface IP data protocol conversion subunit, used for the service data protocol of the Abis interface TDM data processing unit and the Abis interface IP data processing when the handover between the TDM base station and the IP base station occurs The unit's business data protocols are converted between.

The GSM system network according to claim 2 or 4, wherein the format conversion and protocol conversion unit further comprises a format conversion subunit, respectively, and the Abis interface TDM data processing unit and the A interface IP The data processing unit performs communication for compressing the idle voice frame of the service data of the Abis interface TDM data processing unit in the uplink direction, and recovering the idle voice frame of the service data of the A interface IP data processing unit in the downlink direction.

6. A base station controller, comprising:

Abis interface TDM data processing unit, Abis interface IP data processing unit, format conversion and protocol conversion unit, A interface IP data processing unit;

7. The base station controller according to claim 6, wherein the format change The swap and protocol conversion unit includes:

Abis interface IP data and A interface IP data protocol conversion subunit, a protocol for converting the protocol of the service data of the Abis interface IP data processing unit into the service data of the A interface IP data processing unit in the uplink direction, A protocol for converting the protocol of the service data of the A interface IP data processing unit into the service data of the Abis interface IP data processing unit in the downlink direction.

The base station controller according to claim 7, wherein the format conversion and protocol conversion unit further comprises:

Abis interface TDM data and Abis interface IP data protocol conversion subunit, used for the service data protocol of the Abis interface TDM data processing unit and the Abis interface IP data processing when the handover between the TDM base station and the IP base station occurs Protocol conversion between the unit's business data protocols.

The base station controller according to claim 7 or 8, wherein the protocol of the service data of the Abis interface TDM data processing unit comprises a code conversion and rate adaptation unit TRAU/TDM protocol;

The protocol of the service data of the Abis interface IP data processing unit includes: a user datagram protocol UDP/IP protocol;

The protocol of the service data of the A interface IP data processing unit includes: a real-time transport protocol RTP/UDP/IP protocol.

The base station controller according to claim 6 or 8, wherein: the format conversion and protocol conversion unit further comprises a format conversion subunit, and the Abis interface TDM data processing unit and the A interface IP data processing respectively. The unit performs communication for compressing the idle voice frame of the service data of the Abis interface TDM data processing unit in the uplink direction, and the number of services of the A interface IP data processing unit in the downlink direction The idle voice frame is recovered according to it.

The base station controller according to claim 10, wherein the service data compressed in the uplink direction through the idle voice frame includes time information and a frame number.

12. A base station subsystem, comprising: a TDM base station, an IP base station, and

BSC;

The base station subsystem according to claim 12, wherein the format conversion and protocol conversion unit comprises:

14. The base station subsystem of claim 13 wherein: said format The transform and protocol conversion unit also includes:

Abis interface TDM data and Abis interface IP data protocol conversion subunit, used for the service data protocol of the Abis interface TDM data processing unit and the Abis interface IP data when the handover between the TDM base station and the IP base station occurs Protocol conversion between service data protocols of the processing unit.

The base station subsystem according to claim 12, wherein the format conversion and protocol conversion unit further comprises a format conversion subunit, which is respectively performed with the Abis interface TDM data processing unit and the A interface IP data processing unit. The communication is used to compress the idle voice frame of the service data of the Abis interface TDM data processing unit in the uplink direction, and recover the idle voice frame of the service data of the A interface IP data processing unit in the downlink direction.

A method for data transmission, comprising the steps of: receiving service data of a source device;

If the destination device of the service data is a TDM base station, converting the service data into a TDM encapsulation of the Abis interface; or

If the destination device of the service data is an IP base station, converting the service data to an IP encapsulation of the Abis interface; or

If the destination device of the service data is an MSC, converting the service data into an IP encapsulation of the A interface;

Transmitting the converted service data to the destination device.

The method of data transmission according to claim 16, further comprising: compressing the idle voice frame of the service data when the destination device is an MSC and the source device is a TDM base station;

When the destination device is a TDM base station and the source device is an MSC, the idle voice frame of the service data is restored.

18. The method of data transmission according to claim 16, wherein when the handover between the TDM base station and the IP base station occurs, the protocol conversion of the service data includes:

If the TDM base station switches to the IP base station, the service data is The TDM encapsulation of the Abis interface is converted into an IP encapsulation of the Abis interface; or, if the IP base station is handed over to the TDM base station, the service data is converted from the IP encapsulation of the Abis interface to the TDM encapsulation of the Abis interface.

The method of data transmission according to any one of claims 16 to 18, wherein the source device comprises a TDM base station, an IP base station or an MSC, and the destination device comprises a TDM base station, an IP base station or an MSC.

If the destination device of the service data is an MSC, converting the service data into an IP encapsulation of the A interface; or

Transmitting the converted service data to the destination device.

The data transmission method according to claim 20, wherein the source device comprises an IP base station or an MSC, and the destination device comprises an IP base station or an MSC.