JP2002534928A - Data transmission method between base station and mobile switching center - Google Patents

Abstract

SUMMARY The present invention provides a system and method for combining packet data, voice and fax / modem communications within the same communication protocol. According to an exemplary embodiment of the present invention, the value of the unused mode code of a conventional TTL frame is tailored to allow packet data to be incorporated into voice and fax / modem in the TTL frame. As a result, communication resources are used more efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND The present invention relates generally to wireless communication systems, and more particularly to voice, fax /
A system and method for integrating modem and packet data in a cost-effective manner.

[0002] The growth of commercial communication systems and, in particular, the explosive growth of cellular radiotelephone systems, increases the capacity of systems without degrading communication quality beyond the acceptable thresholds of consumers for system designers. I'm looking for a way. At the same time, it is becoming increasingly common for consumers to use mobile communication devices for data transmission over voice. As a desired service for wireless communication systems, the feasibility of using a web browser to send and receive e-mails and access the World Wide Web is frequently being considered. In response, communication system designers
We are looking for a way to efficiently transfer data information to and from mobile users.

There is a fundamental difference between the requirements for data communication and, for example, the requirements for voice communication. For example, the requirements for delay are strict for voice, which is a real-time service, and the requirements for errors are strict for data communications with loose delay constraints. The use of packet data protocols, which are more suitable for data transmission than circuit-switched protocols,
Finally started with a cellular communication system. To handle small amounts of large amounts of data traffic or bursts of traffic, such as those associated with Internet browsing, packet-switched networks use General Packet Radio Service (GPRS), Cellular Digital Packet Data (CDPD). And for providing mobile packet data services as defined by standards such as Personal Digital Cellular (PDC). Unlike circuit-switched data services, mobile packet data services do not require dedicated use of radio resources. For example, in the GPRS standard, each packet of data includes a destination address that provides high-speed settings and allows multiple users to share radio resources.

The integration of packet services for both the Pan-European Digital Mobile Telephony (GSM) cellular system and the Digital Evolved Mobile Telephone System (D-AMPS) cellular system is currently being standardized. . Today, the GSM system
Provides circuit-switched data services that can be used to interconnect with external data networks. Circuit-switched data services are used for both circuit-switched and packet-switched data communications. To make packet-switched data communications more efficient, a new packet-switched data service called General Packet Radio Service (GPRS) has been introduced as part of GSM. Since GPRS is a GSM service, part of the GSM infrastructure is used. These parts of the GSM communication system are described in the European Telecommunications Standards Institute (ETSI) document ET
S 300 574, which is incorporated herein by reference.

[0005] GPRS enables packet-switched communications and supports both connectionless protocols (eg, IP) as well as connection-oriented protocols (eg, X.25). Each channel is configured for either circuit-switched or packet-switched traffic. One of the advantages of the packet-switched data communication protocol is that a single transmission resource can be shared by several users. For this reason, for example, GS
In the case of an M-cellular system, one time slot of a radio frequency carrier may be used by several mobile users for receiving and transmitting data. Shared transmission resources are managed on the network side of the cellular system for both downlink and uplink transmissions.

FIG. 1 shows a typical radio frequency band that supports both circuit-switched and packet-switched traffic in a GPRS system. As shown in FIG. 1, a typical radio frequency band is divided into eight time slots. One timeslot can support a single voice call, a single fax / modem call, or one or more packet data users. For example, time slot 1 is assigned to voice call 1, and time slot 2 is shared by GPRS users 1-3.

[0007] GPRS is very flexible in that it allows for the incorporation of both voice and packet data traffic on a single carrier. However, G
PRS requires significantly more bandwidth than other packet data systems. GPRS requires 25 KHz per timeslot, as compared to 10 KHz per timeslot in other systems (eg, CDPD).

[0008] The CDPD system, which is part of D-AMPS, and the PDC system define a different approach to providing packet data communication than described above. In CDPD systems, there are specific dedicated base stations that handle the transmission of packet data. Thus, voice and packet data traffic are not combined. In a PDC system, a base station includes a separate transceiver that handles packet data communications. In CDPD systems, voice and packet data traffic are not combined.

[0009] Conventional approaches to providing packet data cannot efficiently integrate packet data, voice and fax / modem traffic. Conventional systems adapted to provide both packet data and voice communications have specific base stations, transceivers and channels dedicated to handling packet data transmissions. As a result, communication resources are used inefficiently. Moreover, the cost of the transmission channel is often expensive, making these conventional approaches less cost effective.

There is a need for a system that integrates voice, fax / modem and packet data communications in a cost-effective manner.

SUMMARY The present invention seeks to overcome the above shortcomings by providing a system and method for combining packet data, voice and fax / modem communications within the same communication protocol. According to an exemplary embodiment of the present invention, a conventional TTL
The unused mode code values of the frame are specially tailored to allow the TTL frame to incorporate packet data and voice and fax / modem together. As a result, communication resources are more effectively used.

DETAILED DESCRIPTION The above objects and features of the present invention will become more apparent by reading the following description of preferred embodiments with reference to the accompanying drawings.

In the following description, for purposes of explanation and not limitation, specific details, such as specific circuits, circuit components, techniques, etc., are set forth in order to provide a better understanding of the present invention. However, it is to be understood that the invention can be implemented in embodiments other than these specific details.
It will be apparent to those skilled in the art. In other instances, detailed descriptions of well-known methods, devices, and circuits have been omitted so as not to obscure the description of the present invention.

The exemplary wireless communication system discussed here is described as using a TRA-TRX link (TTL) protocol, where communication between the base station and the mobile switching center is performed by TTL frames. . However, those skilled in the art will appreciate that the concepts disclosed herein are equally applicable to other protocols. Similarly, although some of the exemplary embodiments represent examples for PDC systems, the techniques described herein are equally applicable to wireless base stations in any system.

FIG. 2 is a diagram illustrating a conventional PDC wireless communication system. 2, a conventional system a plurality of mobile stations (MS) 200 ₁ -200 _N, a base station (BS) 210,
It includes a mobile switching center (MSC) 220, a packet mobile switching center (PMSC) 230 connected to a packet network 250 such as the Internet, and a public switched telephone network (PSTN) 240. In operation, it communicates a plurality of mobile stations 200 ₁ -200 _N and the base station 210 in a known manner. Mobile station 200 _1-2
Each of 00 _N, voice, fax / modem data and / or packet
Can send data. Base station 210 receives information from the mobile station via the transceiver, processes the information, and sends the processed information to MSC 220. Base station 210 is MS
Those skilled in the art will also understand that information may be received from C220 and transferred to one or more mobile stations. According to this conventional system, the base station includes separate transceivers for handling voice and fax / modem communications and for handling packet data communications.

At MSC 220, information from base station 210 is transmitted to its destination (ie, PSTN 240 when the information is voice or fax / modem data, and through PMSC 230 when the information is packet data). To the destination of the network 250). Those skilled in the art will appreciate that the network illustrated in FIG. 2 typically includes other components, such as routers (not shown), that help receive, process, and transmit information within the network. Moreover, the number of components shown in FIG. 2 is for simplicity. Wireless communication systems are typically base stations, MSCs, PMSCs
Contains many.

FIG. 3 shows base station 210 and MSC 220 of FIG. 2 in more detail. FIG.
, The base station 210 receives information from the mobile stations 200 ₁ -200 _N via respective antennas 215 and 216 and transmits information to the mobile station, TRX 212.
And TRX213. One of the transceivers, eg TR
X212 handles only packet data communications, while the transceiver TRX213 handles communications related to voice and fax / modem transmissions. Base station 210 also includes a control unit (CU) 214 that controls the routing of information on the lines connecting base station 210 and MSC 220.

The MSC 220 includes a transcoder and a rate matching board (TRAB) 222 that processes information received at the MSC 220 in a well-known manner. TRAB22
2 is associated with the transceiver 213. As a result, TRAB 222 processes and forwards voice and fax / modem information and receives information from PSTN 240. On the other hand, TRX212 is not associated with TRAB. For this reason, the TRX 212 is almost directly connected to the PMSC 230. MSC 220 also includes switching terminal circuits 221, 224, and 225 that operate as switches that forward data to its appropriate destination. Those skilled in the art will appreciate that typical base stations and MSCs typically include more components than shown in FIG. 3 to assist in receiving, transmitting, and processing information.

As described above, the base station 210 includes a transceiver TRX 213 that handles voice and fax / modem communications and a transceiver TX 213 that handles packet data communications.
RX212. Transceivers 212 and 213 communicate with the MSC via line 250. Communication between the TRX 213 and the TRAB 222 is performed using the TTL protocol. The TTL protocol is described in “Single description, TRA-TRX using IMUX / HR” 10/15 14-ANT 244 02 Rev. A,
Which is fully described in the specification and is hereby incorporated by reference and attached as Appendix A. On the other hand, TRX212 and PMSC2
Communication with the H.30 is performed using a different protocol (hereinafter, referred to as "conventional packet data protocol"). This protocol requires a separate channel on line 250.

FIG. 4 shows a conventional TTL frame that can include voice and / or fax / modem information or packet data information. In FIG. 4, the conventional T
The TL frame includes, among other things, a header field containing synchronization information, two sub-fields.
It has a frame and a tail frame. Each sub-frame has three TTs
Includes L individual and extended fields. The term "TTL individual" is used to refer to the TTL resources assigned to a particular TRX and TRAB pair. Each TTL individual includes a data field and a control field. Each data field of a particular frame contains voice and / or fax / modem information, as described above. Each control field of the TTL individual includes the following sub-fields: a quality information sub-field, a dummy data display sub-field, a mode code sub-field, and a cyclic redundancy check (CRC) sub-field. Contains.

[0021] Conventionally, the mode code sub-field was used in the TTL protocol to identify / differentiate different types and rates of service. The encoding of the conventional mode code subfield is shown in Table 1 below. As shown in this table, the conventional TTL protocol does not use a mode code with a value of 8-14. As a result, these values can be used to adapt the TTL protocol to future services.

[0022]

[Table 1]

In Table 1, “AS / FR” represents active voice full rate mode, “AS / HR” represents active voice half rate mode, and “T−
"C / FR" represents through connection full rate mode, "TC / HR" represents through connection half rate mode, and "NS / FR" represents non-voice full rate mode. , “NS / HR” represent the non-voice half rate mode.

As mentioned above, conventional TTL protocols did not provide the ability to incorporate voice and packet data information into a single frame. Thus, TTL frames are dedicated to voice and / or fax / modem information, and transceivers working with TRAB are dedicated to voice and / or fax / modem information. Those skilled in the art will appreciate that due to this limitation, conventional TTL frames may be transmitted TTL-individually unused, thereby wasting valuable communication resources. For example, when voice information using four TTL-individual data fields and packet data having a bandwidth of information included in two TTL-individual data fields are transferred from the base station to the MSC. think of. Using the conventional TTL protocol, the audio information is, for example, the TTL of the TTL frame.
TTL Individuals 2 and 5 remain unused, TTL Individual 0
, 1, 3, and 4. Even though the packet data can be transmitted using the two TTL individual data fields, and thus TTL Individuals 2 and 5, the conventional TTL protocol rejects the transmission of this packet data and returns the packet data. Requests that data be transmitted by a conventional packet data protocol, using an independent MSC to BS channel.

Thus, conventional attempts to provide packet data communication in a wireless communication environment include:
A particular base station, transceiver or channel will result in dedicated handling of that communication. These conventional approaches make the use of communication resources inefficient. The present invention provides a method and system for incorporating packet data communications into voice and fax / modem communications in a cost-effective manner.

FIG. 5 illustrates a base station 310 and an MSC 320 according to an exemplary embodiment of the present invention. As shown, base station 310 has antennas 315 and 31 respectively.
6, two transceivers TRX312 and TRX communicating with one or more mobile stations via
313. According to the present invention, both transceivers 312 and 313 are capable of handling packet data, voice and fax / modem communications. Similar to the system shown previously in FIG. 3, the control unit (CU) 314
And the transfer of information on the line 250 connecting the MSC 320 to the network.

A typical MSC has two transcoders and a speed matching board TRAB32
2 and TRAB323. According to this embodiment, both TRAB 322 and TRAB 323 are capable of processing packet data, voice and fax / modem information. Therefore, each TRAB has a PMSC 230 and a PSTN 24
0 is connected to both. For voice and / or fax / modem transmissions, TRAB processes the information in a well-known manner, as described above. On the other hand, packet
For data transmission, TRAB simply sends the data to its intended destination. Conventional TRABs can be modified by software reprogramming to perform the functions described above.

As in conventional systems, base station 310 and MSC 320 communicate using the TTL protocol. However, in accordance with the present invention, the TTL protocol allows packet data, voice and fax / modem communications to be embedded in a single frame. The present invention uses TTL to represent packet data information.
The unused mode code value 8-13 of the individual control field is used. Table 2 shows the new mode codes for TTL protocol values 8-13.

[0029]

[Table 2]

Those skilled in the art will appreciate that the mode codes described above are merely exemplary and that the mode codes may be adjusted in other ways to suit the needs of a particular network. .

The following examples illustrate the advantages of the present invention. The case where the base station attempts to transfer voice information using the four TTL-individual data fields and packet data having the bandwidth of the information that falls into the two TTL-individual data fields to the MSC. Think again. According to the prior art, voice information and packet data must be transmitted on separate channels from the MSC to the BS, where one TRAB-TRX pair is involved in transmitting voice and the other is TRX is involved in transmitting packet data. However, in accordance with the present invention, a single TRX-TRAB pair and a single MSC to BS channel may be used to transmit both voice information and packet data. Besides, T
Due to changes to the TL protocol, voice and / or fax /
Packet data can be transmitted together with modem information. As a result, valuable communication resources are more efficiently utilized.

The above system and method for incorporating packet data, voice and fax / modem communications in a single TTL frame is simple to implement and cost effective.
This integrated packet data / voice / fax / modem procedure can be implemented by software programming without replacing hardware components. By embedding packet data, voice and fax / modem communications in a single TTL frame, the present invention makes more efficient use of information bandwidth. The present invention also allows a single transceiver to be configured to handle packet data, voice and fax / modem communications, thereby eliminating the need for a dedicated transceiver. As a result, the present invention makes efficient use of communication resources.

The foregoing has described the principles, preferred embodiments, and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments described above. Accordingly, the above-described embodiments are illustrative, not limiting, and various modifications may be made by those skilled in the art to these embodiments without departing from the scope of the invention, which is defined in the claims. It should be understood that

[Brief description of the drawings]

FIG. 1 illustrates a typical radio frequency band supporting both circuit-switched and packet-switched traffic in a GPRS system.

FIG. 2 is a diagram illustrating a conventional PDC wireless communication system.

FIG. 3 is a diagram illustrating the base station 210 and the MSC 220 of FIG. 2 in more detail.

FIG. 4 illustrates a conventional TTL frame that can include either voice and / or fax / modem information or packet data information.

FIG. 5 illustrates a base station and an MSC according to an exemplary embodiment of the present invention.

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Claims (18)

[Claims] 1. A method for transmitting both data and non-data information between a base station and a mobile switching center using a communication protocol, the method comprising: transmitting both the data and the non-data information. Transmitting in a single frame of a communication protocol. 2. The method according to claim 1, wherein said non-data information is audio information. 3. The method of claim 1, wherein said non-data information is fax / modem information. 4. The method according to claim 1, wherein said communication protocol is a TTL protocol. 5. The method of claim 1, wherein the single frame includes a plurality of individual, at least one of the individual carries the data, and at least one of the individual carries the non-data information. 4. The method according to 4. 6. The method of claim 5, wherein each individual includes a plurality of sub-fields, at least one of which identifies the individual as carrying data or non-data information. 7. A means for transmitting data and non-data information in a single frame of a communication protocol, receiving said single frame, sending said data to a first destination and transmitting said non-data information to a second destination. Means for sending to a destination. 8. The system according to claim 7, wherein said non-data information is audio information. 9. The system according to claim 7, wherein said non-data information is fax / modem information. 10. The system of claim 7, wherein the non-data information is both voice and fax / modem information. 11. The system according to claim 7, wherein said communication protocol is a TTL protocol. 12. The single frame includes a plurality of individual,
2. The method of claim 1, wherein at least one of the individual carries the data and at least one of the individual carries the non-data information.
2. The system according to 1. 13. Each individual includes a plurality of sub-fields,
13. The system of claim 12, wherein at least one identifies the individual as carrying data or non-data information. 14. The system of claim 7, wherein said first destination is a packet data network and said second destination is a telephone network. 15. At least one transceiver for processing data and non-data information according to a communication protocol and transmitting said data and non-data information, wherein said data and non-data information is transmitted by said at least one transceiver. , The base station being sent in a single frame of the communication protocol. 16. The base station according to claim 15, wherein the communication protocol is a TTL protocol. 17. The single frame includes a plurality of individual,
2. The method of claim 1, wherein at least one of the individual carries the data and at least one of the individual carries the non-data information.
6. The base station according to 5. 18. Each individual includes a plurality of sub-fields,
18. The base station of claim 17, wherein at least one identifies the individual as carrying data or non-data information.