Efficient radio link adaptation and base station sector selection in a radio communication system

• US 6,542,736 B1
• Filed: 04/04/2000
• Issued: 04/01/2003
• Est. Priority Date: 04/04/2000
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dahlman, Erik, Parkvall, Stefan
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): Nguyen, Huy D
• Application Number:
  US09/542,984
• Time in Patent Office: 1,092 Days
• Field of Search: 455/422, 455/458, 455/62, 455/63, 370/465, 370/468
• US Class Current: 455/452.2
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 28/20 Negotiating bandwidth

Abstract

A mobile terminal sends rapidly changing information relating to the downlink transmission of packet data from a base station sector to the mobile terminal at a higher rate on a fast channel. This rapidly changing information may include, for example, a current data transmission rate and/or a current base station sector identification. Information that changes more slowly, such as the identification of a base station to handle the mobile terminal communication, is communicated to the base station at a lower rate on a slow channel. The information received from the mobile terminal at the higher rate is used by the base station to request a particular sector (and preferably also a sector antenna) to transmit data to the mobile terminal and/or to adjust the current maximum data transmission rate to the mobile terminal. A mobile terminal may also make similar sector/rate requests from plural sectors at the same time as well as from plural sector antennas.

Claims

1. In a radio communications system where mobile terminals communicate with base stations over a radio interface, each base station having plural sectors, a method comprising:

identifying a base station associated with a data transmission to the mobile terminal;

requesting a sector at the base station to transmit data to the mobile terminal;

determining information relating to a data rate associated with the requested sector;

transmitting the requested sector or the information relating to the data rate to the base station at a first rate; and

transmitting an identification of the base station to the base station at a second rate lower than the first rate.

2. The method in claim 1, further comprising:

determining a signal quality of a signal received from the sector, and

determining the data rate based on the signal quality,

wherein the information relating to the data rate is the determined data rate.

3. The method in claim 2, wherein the data rate is a peak or maximum data rate.

4. The method in claim 1, wherein both the requested sector and the data rate information are transmitted to the base station at the first rate.

5. The method in claim 1, wherein each sector includes first and second antennas, the method further comprising:

determining a first antenna data rate associated with the first antenna in the first sector;

determining a second antenna data rate associated with the second antenna in the first sector;

requesting one of the sector antennas; and

transmitting an identification of the requested sector and an identification of the requested one of the first and second sector antennas to the base station at the first rate.

6. The method in claim 5, further comprising:

determining a first signal quality of a signal received from the first sector antenna and a second signal quality of a signal received from the second sector antenna;

determining the first antenna data rate based on the first signal quality; and

determining the second antenna data rate based on the second signal quality.

7. The method in claim 1, further comprising:

identifying a first sector and a second sector at the selected base station as candidates for transmitting data to the mobile terminal;

determining a first sector data rate associated with the first sector;

determining a second sector data rate associated with the second sector; and

transmitting the first sector data rate and the second sector data rate to the base station at the first rate.

8. The method in claim 1, further comprising:

assigning a subchannel to each of the candidate sectors;

transmitting the first sector data rate on its assigned subchannel; and

transmitting the second sector data rate on its assigned subchannel.

9. The method in claim 8, wherein the subchannels are code multiplexed.

10. The method in claim 8, wherein the subchannels are time multiplexed.

11. The method in claim 8, wherein the subchannels correspond to orthogonal codes.

12. In a radio communications system having a base station with plural sectors and a mobile terminal communicating over a radio interface, a method implemented in the mobile terminal comprising sending information relating to a data transmission rate for packet data to be transmitted to the mobile terminal over the radio interface and a sector identification to the base station on a fast channel, and sending an identification of the base station on a slower channel.

13. In a radio communications system where mobile terminals communicate with base stations over a radio interface, each base station having plural sectors, a method comprising:

receiving first information from a mobile terminal at a first rate including a base station identification identifying a base station selected by the mobile terminal to transmit data to the mobile terminal;

receiving second information from the mobile terminal at a second rate higher than the first rate including at least one of a sector identification identifying a sector requested by the mobile terminal to transmit data to the mobile terminal and data associated with a transmission rate at which to transmit that data; and

if the base station is identified, transmitting data to the mobile terminal based on the received second information.

14. The method in claim 13, wherein the second information includes both the sector identification and the data associated with the transmission rate.

15. The method in claim 13, wherein the second information includes the sector identification and the base station includes a storage queue of data packets to be sent to the mobile terminal, the method further comprising:

sending the data in the storage queue from the identified sector to the mobile terminal.

16. The method in claim 13, wherein the second information includes the data transmission rate, the method further comprising:

sending the data at the data transmission rate.

17. The method in claim 16, further comprising:

adapting an amount of coding of the data to accommodate the data transmission rate.

18. The method in claim 16, further comprising:

adapting a type of data modulation to accommodate the data transmission rate.

19. The method in claim 16, wherein a number of data packets is increased or decreased per unit of time to accommodate the data transmission rate.

20. The method in claim 16, wherein a size of a data packet is increased or decreased to accommodate the data transmission rate.

21. The method in claim 13, wherein the second information includes the data associated with the transmission rate and the data is a signal quality indicator, the method further comprising:

determining a data transmission rate using the signal quality indicator, and

sending the data at the data transmission rate.

22. The method in claim 13, further comprising:

receiving the second information from the mobile terminal for plural sectors, and

requesting one of the plural sectors to send the data to the mobile terminal.

23. The method in claim 22, further comprising:

receiving the second information from plural mobile terminals, wherein the second information from each of the mobile terminals identifies plural sectors, and

requesting one of the plural sectors for each of the mobile terminals so that data throughput to each of the plural mobile terminals is optimized.

24. The method in claim 13, wherein each sector includes plural antennas, the method further comprising:

receiving the second information from the mobile terminal for the plural antennas, and

requesting one of the plural antennas to send the data to the mobile terminal.

25. The method in claim 24, further comprising:

receiving the second information from plural mobile terminals, wherein the second information from each of the mobile terminals identifies plural antennas, and

requesting one of the plural sectors and one of the plural antennas for each of the mobile terminals so that data throughput to each of the plural mobile terminals is optimized.

26. The method in claim 13, wherein the second rate is high enough to track rapid changes in radio channel conditions.

27. A radio communications system comprising:

plural base stations, each of the plural base stations including plural sectors;

plural mobile terminals communicating with a base station over a radio interface,

wherein a mobile terminal sends information relating to a data transmission rate for packet data to be transmitted to the mobile terminal over the radio interface and a sector identification to the base station on a fast radio channel and sends an identification of the base station on a slower radio channel, and

wherein the identified base station transmits the packet data from the identified sector using the information relating to the data transmission rate.

28. The system in claim 27, wherein the information relating to the data transmission rate includes a maximum data transmission rate from the requested sector under current radio channel conditions for a particular performance level.

29. The system in claim 27, wherein the information relating to the data transmission rate includes a signal quality indicative of the radio channel condition between the requested sector and the mobile terminal.

30. The system in claim 27, wherein the identified sector adapts an amount of data coding or a type of data modulation in order to transmit the packet data at the data transmission rate.

31. In a radio communications system where mobile terminals communicate with base stations over a radio interface, each base station having plural sectors, a mobile terminal comprising:

data processing circuitry;

signal processing and radio transceiving circuitry coupled to the data processing circuitry,

wherein the data processing circuitry is configured to perform the following tasks;

identifying a base station associated with a data transmission to the mobile terminal;

identifying a sector at the base station to transmit data to the mobile terminal; and

determining information relating to a data rate associated with the sector, and

the signal processing and transceiving circuitry is configured to perform the following tasks;

transmitting one of an identification of the sector and the information relating to the data rate to the base station at a first rate, and

transmitting an identification of the base station to the base station at a second rate lower than the first rate.

32. The mobile terminal in claim 31, further comprising:

a signal quality detector for determining a signal quality of a signal received from the sector,

wherein the data processing circuitry is further configured to determine the data rate based on the signal quality.

33. The mobile terminal in claim 31, further comprising:

a signal quality detector for determining a signal quality of a signal received from the sector,

wherein the information relating to the data rate is the determined signal quality.

34. The mobile terminal in claim 31, wherein the data rate is a peak or maximum data rate requested under current conditions.

35. The mobile terminal in claim 31, wherein both the sector identification and the first data rate are transmitted to the base station at the first rate.

36. The mobile terminal in claim 31, wherein each sector includes first and second antennas and the data processing circuitry is further configured to:

determine a first antenna data rate associated with the first antenna in the first sector;

determine a second antenna data rate associated with the second antenna in the first sector;

request one of the sector antennas; and

transmit an identification of the sector and an identification of the requested one of the first and second sector antennas to the base station at the first rate via the signal processing and transceiving circuitry.

37. The mobile terminal in claim 31, further comprising:

a signal quality detector for determining a signal quality of a first signal quality of a signal received from the first sector antenna and a second signal quality of a signal received from the second sector antenna,

wherein the data processing circuitry is further configured to;

determine the first antenna data rate based on the first signal quality; and

determine the second antenna data rate based on the second signal quality.

38. The mobile terminal in claim 31, wherein the data processing circuitry is further configured to:

identify a first sector and a second sector at the selected base stations as candidates for transmitting data to the mobile terminal;

determine a first sector data rate associated with the first sector; and

determine a second sector data rate associated with the second sector,

wherein the signal processing and transceiving circuitry is further configured to;

transmit the first sector data rate and the second sector data rate to the base station at the first rate.

39. The mobile terminal in claim 31, wherein the data processing circuitry is further configured to assign a subchannel to each of the candidate sectors, and

wherein the signal processing and transceiving circuitry is further configured to:

transmit the first sector data rate on its assigned subchannel; and

transmit the second sector data rate on its assigned subchannel.

40. In a radio communications system where mobile terminals communicate with base stations over a radio interface, base station comprising:

data processing circuitry, and

plural sectors, each sector including signal processing and transceiving circuitry;

wherein the data processing circuitry is configured to perform the following tasks;

receive first information from a mobile terminal at a first rate including a base station identification identifying a base station to transmit data to the mobile terminal, and

receive second information from the mobile terminal at a second rate higher than the first rate including at least one of a sector identification identifying a sector to transmit data to the mobile terminal and data associated with a transmission rate at which to transmit that data; and

wherein the data is transmitted to the mobile terminal based on the received second information.

41. The base station in claim 40, wherein the second information includes both the sector identification and the data transmission rate.

42. The base station in claim 40, wherein the second information includes the sector identification and the data processing circuitry includes a storage queue of data packets to be sent to the mobile terminal and is further configured to send the data in the storage queue from the identified sector to the mobile terminal.

43. The base station in claim 40, wherein the second information includes the data transmission rate, and the data processing circuitry is configured to send the data at the data transmission rate.

44. The base station in claim 43, wherein each sector includes a channel coder, and the data processing circuitry is configured to regulate the channel coder to accommodate the data transmission rate.

45. The base station in claim 43, wherein each sector includes a modulator, and the data processing circuitry is configured to regulate the modulator to accommodate the data transmission rate.

46. The base station in claim 40, wherein the second information includes the data associated with the transmission rate and the data is a signal quality indicator, and the data processing circuitry is configured to determine a data transmission rate using the signal quality indicator.

47. The base station in claim 40, wherein the second information is received from the mobile terminal for plural sectors, and the data processing circuitry is configured to request one of the plural sectors to send the data to the mobile terminal.

48. The base station in claim 47, wherein the second information is received from plural mobile terminals and the second information from each of the mobile terminals identifies plural sectors, and wherein the data processing circuitry is configured to request one of the plural sectors for each of the mobile terminals to improve data throughout.

49. The base station in claim 40, wherein each sector includes plural antennas and the second information received from the mobile terminal is for the plural antennas, and wherein the data processing circuitry is configured to request one of the plural antennas to send the data to the mobile terminal.

50. The base station in claim 49, wherein the second information is received from plural mobile terminals and the second information from each of the mobile terminals identifies plural antennas, and wherein the data processing circuitry is configured to request one of the plural sectors and one of the plural antennas for each of the mobile terminals to improve data throughput.

51. The base station in claim 40, wherein the second rate is high enough to track rapid changes in radio channel conditions.