Decentralized base station for reducing bandwidth requirements for communications to and from radio transmitter-receivers in a telecommunications network

• US 5,555,260 A
• Filed: 08/24/1995
• Issued: 09/10/1996
• Est. Priority Date: 02/25/1994
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Rinnback, Hans L., Israelsson, Per V., Halen, Hakan M.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US08/519,016
• Time in Patent Office: 383 Days
• Field of Search: 370/29, 370/84, 370/85.7, 370/95.1, 370/95.3, 370/109, 370/118, 455/33.1, 455/53.1, 455/54.1, 455/54.2, 455/72, 379/63, 375/240
• US Class Current: 370/347
• CPC Class Codes: H04J 3/1635 Format conversion, e.g. CEPT/US
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04Q 11/0435 Details
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A TDMA cellular mobile radio system has at least one network control unit, at least one radio transceiver, and at least one multiplexor for multiplexing and demultiplexing digitally encoded and compressed speech data transmitted between the network control unit and radio transceiver. The bandwidth of the speech data is reduced through compression. The bandwidth of the speech data required on a radio transceiver side of the multiplexor is further reduced by buffering the speech data arriving at the multiplexor at a relatively high modulation rate, retransmitting the buffered speech data at a relatively lower modulation rate, buffering the speech data arriving from the multiplexor at a relatively lower modulation rate, and retransmitting the buffered speech data at a relatively higher modulation rate.

Claims

1. An apparatus for reducing bandwidth requirements in a cellular TDMA telecommunications network comprising:

at least one network control unit;

at least one base station connected to the at least one network control unit, the at least one base station comprising a multiplexing means and at least one transceiver means;

means for digitally encoding and compressing speech data to be transmitted to the at least one base station and outputting the digitally encoded and compressed speech data to the at least one network control unit;

a first communications link between the at least one network control unit and the multiplexing means comprising a high speed link adapted to transmit at a speed of at least 1 Mbps;

a second communications link between the multiplexing means and the at least one transceiver means comprising a low speed link adapted to transmit at a speed under 1 Mbps; and

the multiplexing means comprising;

buffering means for buffering the digitally encoded and compressed speech data being transmitted toward the at least one transceiver at a relatively higher transmission rate and retransmitting the buffered speech data at a relatively lower transmission rate; and

buffering means for buffering the digitally encoded and compressed speech data arriving from the at least one transceiver at a relatively lower transmission rate and retransmitting the buffered speech data at a relatively higher transmission rate.

2. The apparatus of claim 1, wherein the second communications link comprises a 2-wire interface.

3. The apparatus of claim 1, wherein the second communications link comprises a 4-wire interface.

4. The apparatus of claim 1, wherein the low speed link transmits at a rate of about 192 kbps.

5. The apparatus of claim 1, wherein the second communications link comprises two 2-wire pairs.

6. The apparatus of claim 1, wherein the second communications link comprises ISDN interface lines.

7. The apparatus of claim 1, wherein the second communications link comprises a high-bit-rate digital subscriber interface line.

8. The apparatus of claim 1, wherein the high speed link comprises a transmission link transmitting at a rate of about 2048 kbps according to GSM specifications.

9. The apparatus of claim 1, comprising:

wherein the cellular telecommunications network is a GSM system and the at least one network control unit comprises at least one base station controller.

10. A cellular TDMA telecommunications network, comprising:

a decentralized base station;

at least one mobile services switching center;

transcoder means provided remotely from the base station for digitally encoding and compressing speech data to be transmitted to the base station;

at least one transceiver for communicating with mobile stations;

a network control unit adapted to receive the digitally encoded and compressed speech data from said transcoder means;

a transceiver interface for interfacing between the network control unit and the at least one transceiver;

a first communications link connected between the network control unit and the transceiver interface, the first communications link being adapted to transmit the digitally encoded and compressed speech data at a relatively high transmission rate;

at least one second communications link connected between the transceiver interface and each of the at least one transceivers, the at least one second communications link being adapted to transmit the digitally encoded and compressed speech data at a rate relatively lower than the transmission rate of the first communications link;

means provided in the transceiver interface, for adapting the rate of the first communications link to the lower rate of the at least one second communications link.

11. The decentralized base station of claim 10, wherein the at least one second communications link comprises 2 or 4 wire connections.

12. The decentralized base station of claim 10, wherein at least one of the at least one transceiver is disposed at a location remote from the transceiver interface.

13. The decentralized base station of claim 10, wherein the at least one of the at least one transceiver is disposed at a location proximate to the transceiver interface.

14. The decentralized base station of claim 10, wherein the cellular telecommunications network is a GSM system and the network control unit comprises at least one base station controller.

15. The decentralized base station of claim 10, wherein the high transmission rate of the first communications link is about 2 Mbps and the low transmission rate of the second communications link is about 192 kbps.

16. The decentralized base station of claim 10, wherein said at least one transceiver comprise a first connector for low speed remote connection adapted to be connected to said at least one second communications link and a second connector for high speed local connection.