Radio communication system with diversity reception on a time-slot by time-slot basis

• US 5,991,282 A
• Filed: 05/28/1997
• Issued: 11/23/1999
• Est. Priority Date: 05/28/1997
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Langlet, Carl Erik Joakim, Granstrom, Bo Anders
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): Nguyen, Kim T.
• Application Number:
  US08/864,684
• Time in Patent Office: 909 Days
• Field of Search: 370/331, 370/332, 370/333, 370/334, 370/337, 370/264, 370/347
• US Class Current: 370/332
• CPC Class Codes: H04L 1/06 using space diversity

Abstract

A communication system base station improves uplink coverage on a time slot by time slot basis. The coverage is improved by allocating diversity and non-diversity time-slots based on received signal quality of an RF link between a mobile station and a base station. The diversity time-slots are time slots during which information is received by more receiver branches than during the non-diversity time-slots.

Claims

1. A digital communication system for providing communication coverage over radio frequency (RF) channels that are subdivided into a plurality of time slots during which information is communicated with at least one mobile station, comprising:

a base station including a plurality of receiver branches for receiving uplink data from the mobile station on selected ones of a number of diversity and non-diversity time-slots, wherein the diversity time-slots are time slots during which the uplink data is received by more receiver branches than the non-diversity time-slots; and

a controller that allocates diversity and non-diversity time-slots based on a measure of received signal quality of at least one of the RF channels linking the mobile station to the base station.

2. The communication system of claim 1, wherein the measure of received signal quality corresponds to at least one of a measure of the received signal strength at the base station, or a measure of bit error rate at the base station, or a frame erasure rate at the base station.

3. The communication system of claim 1, wherein the base station measures the quality of idle RF channels, wherein the controller is responsive to the measure of idle channel quality for selecting the diversity and non-diversity time-slots.

4. The communication system of claim 1, wherein the base station includes an equalizer for combining the uplink data.

5. The communication system of claim 1, wherein the base station includes a baseband bus for selective addressing of the receiver branches used for reception during the non-diversity or diversity time-slots.

6. The communication system of claim 1, wherein the controller allocates the diversity and non-diversity time-slots based on fault reports received from the base station.

7. The communication system of claim 1, wherein the antennas are configured for space diversity.

8. The communication system of claim 1, wherein the antennas are dual polarized antennas.

9. The communication system of claim 1, wherein the controller performs an intra-base-station hand over for switching reception between a non-diversity time slot and a diversity time slot.

29. The communication system of claim 1, wherein the controller dynamically reallocates the diversity and non-diversity time-slots based on operating requirements of the system.

10. A base station for transmitting and receiving information over RF channels that are subdivided into a plurality of time slots during which the information is communicated with at least one mobile station, comprising:

a plurality of receiver branches for receiving uplink information from the mobile station on any one of a number of non-diversity and diversity time-slots, wherein the diversity time-slots are time slots during which the uplink data is received by more receiver branches than during the non-diversity time-slots; and

a controller that allocates diversity and non-diversity time-slots based on a measure of received signal quality of at least one of the RF channels linking the mobile station to the base station.

11. The base station of claim 10, wherein the measure of received signal quality corresponds to at least one of a measure of the received signal strength at the base station, or a measure of bit error rate at the base station, or a frame erasure rate at the base station.

12. The base station of claim 10, wherein the base station measures the quality of idle RF channels, wherein the controller is responsive to the measure of idle channel quality for selecting the diversity and non-diversity time-slots.

13. The base station of claim 10, wherein the base station includes an equalizer for combining the uplink data.

14. The base station of claim 10, wherein the base station includes a baseband bus for selective addressing of the receiver branches used during the non-diversity or diversity time-slots.

15. The base station of claim 10, wherein the controller allocates the diversity and non-diversity time-slots based on fault reports received from the base station.

16. The base station of claim 10, wherein the antennas are configured for space diversity.

17. The base station of claim 10, wherein the antennas are dual polarized antennas.

18. The base station of claim 10, wherein the controller performs an intra-base-station hand over for switching reception between a non-diversity time slot and a diversity time slot.

30. The base station of claim 10, wherein the controller dynamically reallocates the diversity and non-diversity time-slots based on operating requirements of the system.

19. A method for receiving uplink data from at least one mobile station over at least one radio frequency (RF) channel that is subdivided into a plurality of time slots, comprising:

receiving the uplink data from the mobile station during a selected one of a number of diversity and non-diversity time-slots, wherein the non-diversity time-slots are time slots during which the uplink data is received using less receiver branches than during the diversity time-slots; and

allocating the diversity and non-diversity time-slots based on a measure of received signal quality of at least one of the RF channels linking the mobile station to the base station.

20. The method for receiving uplink data according with claim 19 further including combining the uplink data received during at least the diversity time slots.

21. The method for receiving uplink data according with claim 20, wherein combining is performed on data received from selected receiver branches over a baseband bus.

22. The method for receiving uplink data according with claim 21, wherein the combining of the uplink data is performed by an equalizer.

23. The method for receiving uplink data according with claim 19, wherein the measure of received signal quality corresponds to a measure of the received signal strength at the base station, or a measure of bit error rate at the base station, or a frame erasure rate at the base station.

31. The method of claim 19, wherein the diversity and non-diversity time-slots are dynamically reallocated based on operating requirements of the system.

24. An apparatus for receiving uplink data from at least one mobile station over at least one radio frequency (RF) channel that is subdivided into a plurality of time slots, comprising:

receiver branches that receive the uplink data from the mobile station during a selected one of a number of diversity and non-diversity time-slots, wherein the non-diversity time-slots are time slots during which the uplink data is received using less receiver branches that than during the diversity time-slots; and

means for allocating the diversity and non-diversity time-slots based on a measure of received signal quality of at least one of the RF channels linking the mobile station to the base station.

25. The apparatus for receiving uplink data according with claim 24 further including a combiner that combines the uplink data received during at least the diversity time slots.

26. The apparatus for receiving uplink data according with claim 25, wherein the combiner includes means for receiving data from selected receiver branches over a baseband bus.

27. The apparatus for receiving uplink data according with claim 25, wherein the combiner includes an equalizer that combines the uplink data.

28. The apparatus for receiving uplink data according with claim 24, wherein the measure of received signal quality corresponds to a measure of the received signal strength at the base station, or a measure of bit error rate at the base station, or a frame erasure rate at the base station.

32. The apparatus of claim 24, wherein the controller dynamically reallocates the diversity and non-diversity time-slots based on operating requirements of the system.