Reuse of a physical control channel in a distributed cellular radio communication system

• US 6,108,550 A
• Filed: 06/12/1998
• Issued: 08/22/2000
• Est. Priority Date: 06/13/1997
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wiorek, Jonas, Beming, Per, Frodigh, Magnus, Wallstedt, Kenneth
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): LEGREE, TRACY MICHELLE
• Application Number:
  US09/095,941
• Time in Patent Office: 802 Days
• Field of Search: 455/434, 455/447, 455/515, 455/509, 455/511, 455/516, 455/450-455, 455/503, 455/502, 455/446, 370/337, 370/329, 370/349
• US Class Current: 455/447
• CPC Class Codes: H04W 74/002 Transmission of channel access control information

Abstract

The present invention relates to the reuse of a control channel in a distributed cellular radio communication system. At least one physical channel, the so called physical control channel, in the radio communication system is used for transferring logical control channels. According to the present invention the physical uplink control channel can be reused with respect to logical control channels comprising an access request. The physical downlink control channel can be reused with respect to logical control channels comprising a message that access is granted to a mobile station or a message that someone requests contact with a mobile station. According to the invention the physical uplink control channel and/or the physical downlink control channel is reused. This means that more connections per time unit may be established in the radio communication system.

Claims

1. A method for the reuse of physical control channels in at least one cell in a distributed cellular radio communication system, said distributed cellular radio communication system comprising at least one mobile station and a number of radio units, wherein at least one cell comprises a number of radio units controlled by at least one central unit, said mobile stations communicating with said radio units through connections comprising physical uplink and downlink channels, wherein said physical uplink and downlink channels transfer logical uplink and downlink channels, respectively and wherein at least one physical uplink channel and at least one physical downlink channel in the cell are designated as the physical uplink control channel and the physical downlink control channel respectively, for transferring logical uplink and downlink control channels respectively, said method in each cell comprising the following steps:

a) simultaneously receiving signals on the physical uplink control channel for each radio unit, wherein said received signals can transfer different information;

b) identifying the type of logical uplink channels transmitted on said physical uplink control channel;

c) interpreting the information in the logical control channel of the type access channel, referred to as the logical access channel wherein said information comprises a request for contact with the radio communication system;

d) generating logical downlink control channels in dependence of said interpretation;

e) mapping the logical downlink control channels mentioned in step d) onto the physical downlink control channel for each radio unit;

f) simultaneously transmitting signals on the physical downlink control channel from each radio unit, whereby different information in the logical downlink control channels may be transmitted on the physical control channel from different radio units in the cell.

2. A method according to claim 1, further comprising separately demodulating received bit streams for the respective radio unit.

3. A method according to claim 1, further comprising separately modulating bit streams to be transmitted for the respective radio unit.

4. A method according to claim 1, wherein the receiving radio units are divided into groups of at least two radio units, said method further comprising separately demodulating received bit streams for the respective group of radio units.

5. A method according claim 1, wherein the radio units are divided into groups of at least two radio units, said method further comprising separately modulating bit streams to be transmitted for the respective group of radio units.

6. A method according to claim 1, wherein the received signals are broadband signals comprising signals on all physical uplink channels allowed in the cell.

7. A method according to claim 6, wherein the broadband signals are separated into physical channels.

8. A method according to claim 1, wherein the received signals are separated into physical channels.

9. A method according to claim 1, wherein said interpreting step further comprises registering the radio units that have received information on the logical access channel and determining from which mobile stations the respective logical access channel has been received.

10. A method according to claim 1, wherein said interpreting step further comprises registering and interpreting the signal strengths of the received signals on the respective logical access channels.

11. A method according to claim 1, wherein said radio communication system is a GSM system and wherein said logical access channels are RACH channels.

12. A method according to claim 1, wherein said radio communication system is a packet switched GSM system according to GPRS and wherein said logical access channels are PRACH channels.

13. A method according to claim 1, wherein said generating step further comprises the steps of:

determining the mobile stations that are to be given access to the radio communication system based on said interpretation; and

generating allocation channels comprising a message to the effect that a mobile station is granted access to the radio communication system, to said mobile stations that are to be given access.

14. A method according to claim 13, wherein said radio communication system is a GSM system and wherein said allocation channels are AGCH channels.

15. A method according to claim 13, wherein said radio communication system is a packet switched GSM system according to GPRS and wherein said allocation channels are PAGCH channels.

16. A method according to claim 15, wherein said radio communication system is a GSM system and wherein said paging channels are PCH channels.

17. A method according to claim 15, wherein said radio communication system is a packet switched GSM system according to GPRS and wherein said paging channels are PPCH channels.

18. A method according to claim 13, wherein said generating step further comprises generating dummy bursts to the radio units that are not to transmit an access message.

19. A method according to claims 13, wherein said generating step further comprises generating copies of allocation channels already generated to the radio units that are not to transmit an allocation channel of their own.

20. A method according to claim 13, wherein said generating step further comprises generating paging channels comprising messages to the effect that the radio communication system requests contact with a certain mobile station, to the radio units that are not to transmit an access message of their own.

21. A method for the reuse of physical control channels in at least one cell in a distributed cellular radio communication system, said distributed cellular radio communication system comprising at least one mobile station and a number of radio units, wherein at least one cell comprises a number of radio units controlled by at least one central unit, said mobile stations communicating with said radio units through connections comprising physical uplink and downlink channels, wherein said physical uplink and downlink channels transfer logical uplink and downlink channels, respectively and wherein at least one physical uplink channel and at least one physical downlink channel in the cell are designated as the physical uplink control channel and the physical downlink control channel respectively, for transferring logical uplink and downlink control channels respectively, said method in each cell comprising the following steps:

a) simultaneously receiving signals on the physical uplink control channel for each radio unit, wherein said received signals can transfer different information;

b) identifying the type of logical uplink channels transmitted on said physical uplink control channel;

c) interpreting the information in the logical control channel of the type access channel, referred to as the logical access channel, wherein said information comprises a request for contact with the radio communication system;

d) generating logical downlink control channels of the type common control channels in dependence of said interpretation;

e) mapping one of the logical downlink control channels generated in step d) onto the physical downlink control channel for each radio unit;

f) transmitting signals on the physical downlink control channel from all radio units;

g) repeating steps e) and f).

22. A method according to claim 21, further comprising separately demodulating received bit streams for the respective radio unit.

23. A method according to claim 21, wherein the radio units are divided into groups of at least two radio units, said method further comprising separately demodulating received bit streams for the respective group of radio units.

24. A method for the reuse of physical control channels in at least one cell in a distributed cellular radio communication system, said distributed cellular radio communication system comprising at least one mobile station and a number of radio units, wherein at least one cell comprises a number of radio units controlled by at least one central unit, said mobile stations communicating with said radio units through connections comprising physical uplink and downlink channels, wherein said physical uplink and downlink channels transfer logical uplink and downlink channels, respectively, and wherein at least one physical uplink channel and at least one physical downlink channel in the cell are designated as the physical uplink control channel and the physical downlink control channel respectively, for transferring logical uplink and downlink control channels respectively, said method in each cell comprising the following steps:

a) receiving signals on the physical uplink control channel for all radio units at different points in time, wherein only one signal may be received at one point in time, which received signals can transfer different information;

b) identifying the type of logical uplink channels transmitted on said physical uplink control channel at each point in time;

c) interpreting the information in each logical uplink channel of the type access channel, referred to as the logical access channel, wherein said information comprises a request for contact with the radio communication system;

d) generating a logical downlink control channel for each radio unit in dependence of said interpretation;

e) mapping the logical downlink control channels mentioned in step d) onto the physical control channel for each radio unit;

f) simultaneously transmitting signals on the physical downlink control channel from each radio unit, wherein different information in the logical downlink control channels may be transmitted on the physical control channel from different radio units in the cell.

25. A method according to claim 24, further comprising separately modulating bit streams to be transmitted for the respective radio unit.

26. A method according to claim 24, wherein the transmitting radio units are divided into groups of at least two radio units, said method further comprising separately modulating bit streams to be transmitted for the respective group of radio units.

27. A distributed cellular radio communication system for reuse of physical control channels in at least one cell in a distributed cellular radio communication system, said distributed cellular radio communication system comprising:

least one mobile station and a number of radio units, wherein at least one cell comprises a number of radio units controlled by at least one central unit, said mobile stations communicating with said radio units through connections comprising physical uplink and downlink channels, wherein said physical uplink and downlink channels transfer logical uplink and downlink channels, respectively, and wherein at least one physical uplink channel and at least one physical downlink channel in the cell are designated as the physical uplink control channel and the physical downlink control channel respectively, for transferring logical uplink and downlink control channels respectively;

receiver means for receiving signals on physical uplink channels for each radio unit, wherein said received signals can transfer different information;

channel separating means for separating received bit streams on a physical uplink channel and a logical uplink channel and for identifying the logical uplink channel transferred on said physical uplink channel;

interpretation means for interpreting the information in the logical control channels of the type access channel, referred to as the logical access channels, wherein said information comprises a request for contact with the radio communication system;

decoding means for decoding the information transferred on said logical access channels;

generating means for generating logical downlink control channels in dependence of said interpretation;

channel generating means for mapping said logical downlink control channels onto the physical downlink control channel;

transmitting means for transmitting signals on the physical control channel from each radio unit, said signals being able to transfer different information; and

supervision means for controlling and supervising said means.

28. A distributed cellular radio communication system according to claim 27, wherein said receiver means are arranged to receive signals on the physical uplink control channel simultaneously from the respective radio unit.

29. A distributed cellular radio communication system according to claim 27, wherein said receiver means are arranged to receive only one signal on the physical uplink control channel at a particular point in time from the respective radio unit.

30. A distributed cellular radio communication system according to claim 27, wherein said transmitting means are arranged to be able to transmit different signals simultaneously on the physical downlink control channel from the respective radio unit.

31. A distributed cellular radio communication system according to claim 27, wherein said transmitting means are arranged to be able to transmit the same signal at a particular point in time on the physical downlink control channel from the respective radio unit.

32. A distributed cellular radio communication system according to claim 27, wherein the radio communication system is a GSM system.

33. A distributed cellular radio communication system according to claim 32, wherein the radio communication system is a packet switched GPRS system.