Method and arrangement for managing a reference signal for uplink channel estimation in a communications system

• US 8,121,106 B2
• Filed: 03/24/2006
• Issued: 02/21/2012
• Est. Priority Date: 03/24/2006
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Furuskar, Anders, Skillermark, Per
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): Masur, Paul
• Application Number:
  US12/293,742
• Publication Number:
  US 20100165894A1
• Time in Patent Office: 2,160 Days
• Field of Search: 370/295, 370/319, 370/332, 370/344, 370/480, 455/522
• US Class Current: 370/344
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1484 operating bytewise

Abstract

An object of the present invention is to provide a mechanism of measuring a reference signal that is less over head consuming and less time consuming. The object is achieved by a method for managing uplink channel estimation in a base station. The base station is comprised in a radio access network using Frequency Division Duplex (FDD). The base station is associated with a first cell of a number of cells within the radio access network. The base station is adapted to connect at least one mobile terminal, being situated in the first cell, to a network infrastructure. The method comprises the step of transmitting a redirected reference signal on an uplink band to the mobile terminal. The redirected reference signal is intended for uplink channel estimation.

Claims

1. A method for managing uplink channel estimation in a base station, which base station is comprised in a radio access network using Frequency Division Duplex (FDD), the base station being associated with a first cell of a number of cells within the radio access network, the base station being adapted to connect at least one mobile terminal being situated in the first cell, to a network infrastructure, the method comprising the steps of:

transmitting a redirected reference signal in an uplink band from the base station to the mobile terminal, said redirected reference signal being intended for uplink channel estimation;

receiving a report from the mobile terminal that received the redirected reference signal, the report comprising the uplink channel quality estimated by the terminal by knowing the origin redirected reference signal transmitted from the base station, estimating the redirected reference signal, and comparing the known origin redirected reference signal with the received redirected reference signal; and

performing uplink quality-based frequency-domain scheduling based on the uplink channel quality comprised in the report.

2. The method of claim 1, wherein the step of transmitting the redirected reference signal is performed time multiplexed.

3. The method of claim 1, wherein the step of transmitting the redirected reference signal is performed such that it covers the entire uplink frequency band.

4. The method of claim 1, wherein the redirected reference signal is surrounded by a guard period.

5. The method of claim 4, wherein the guard period is 60-70 μ

s.

6. The method of claim 1, wherein the step of transmitting the redirected reference signal is performed by frequency multiplexing.

7. The method of claim 1, wherein the frequency of transmitting the redirected reference signal is adapted in accordance with a channel coherence time.

8. The method of claim 7, wherein the channel coherence time is estimated as Tc =c/(f*v), where c is a speed of light, f is a carrier frequency, and v is a speed of the mobile terminal.

9. The method of claim 1, wherein the redirected reference signal is transmitted every 5-10 ms frame, preferably in every 10 ms frame.

10. The method of claim 1, wherein multiple redirected reference signals are transmitted per time frame.

11. The method of claim 1, wherein the radio access network uses WINNER technology, wherein the redirected reference signal is transmitted in the first part of a super-frame.

12. The method of claim 1, wherein the uplink quality based frequency domain scheduling is performed by input the received channel quality to the scheduling algorithm for uplink quality based frequency domain scheduling in the time and/or in the frequency domain.

13. The method of claim 1, wherein the method comprises the further steps of:

receiving a regular uplink reference signal from the terminal, and estimating the uplink channel quality, based on the received regular reference signal.

14. The method of claim 13, wherein the channel quality, based on the received regular reference signal, is used as a further input to a scheduling algorithm for uplink quality based frequency domain scheduling in at least one or both of the time domain and the frequency domain.

15. The method of claim 1, the method comprising the further steps of:

transmitting an uplink control message on a downlink channel to the mobile terminal based on the performed uplink quality based frequency domain scheduling.

16. A computer program product for managing uplink channel estimation in a base station, comprising a non-transitory computer-readable medium encoded with computer program code, the code operable, when executed by a processor, to:

transmit a redirected reference signal in an uplink band from a base station to at least one mobile terminal connected to the base station, said redirected reference signal being intended for uplink channel estimation;

receive a report from the mobile terminal that received the redirected reference signal, the report comprising the uplink channel quality estimated by the terminal by knowing the origin redirected reference signal transmitted from the base station, estimating the redirected reference signal, and comparing the known origin redirected reference signal with the received redirected reference signal; and

perform uplink quality-based frequency-domain scheduling based on the uplink channel quality comprised in the report.

17. An arrangement in a base station being comprised in a radio access network using Frequency Division Duplex, the base station being associated with a first cell of a number of cells within the radio access network, the base station being adapted to connect at least one mobile terminal being situated in the first cell, to a network infrastructure, the base station arrangement comprising:

a transmitter for transmitting a redirected reference signal on an uplink band to the mobile terminal, said redirected reference signal being intended for uplink channel estimation;

a receiver arranged for receiving a report from the mobile terminal that has received the redirected reference signal, the report comprising the uplink channel quality, estimated by the mobile terminal by knowing the origin redirected reference signal transmitted by the base station, estimating the received redirected reference signal and comparing the known origin redirected reference signal with the received redirected reference signal; and

means for performing uplink quality-based frequency-domain scheduling based on the uplink channel quality comprised in the report.

18. The base station arrangement of claim 17, wherein the transmitter is adapted to transmit the redirected reference signal time multiplexed.

19. The base station arrangement of claim 17, wherein the transmitter further is adapted to transmit the redirected reference signal such that it covers the entire uplink frequency band.

20. The base station arrangement of claim 17, wherein the transmitter further is adapted to transmit the redirected reference signal surrounded by a guard period.

21. The base station arrangement of claim 20, wherein the guard period is 60-70 μ

s.

22. The base station arrangement of claim 17, wherein the transmitter is adapted to transmit the redirected reference signal frequency multiplexed.

23. The base station arrangement of claim 17, wherein the transmitter is arranged to transmit the redirected reference signal with a frequency that is adapted in accordance with the channel coherence time.

24. The base station arrangement of claim 23, wherein the channel coherence time is estimated as Tc =c/(f*v), where c is a speed of light, f is a carrier frequency and v is a speed of the mobile terminal.

25. The base station arrangement of claim 17, wherein the transmitter is arranged to transmit the redirected reference signal in every 5-10 ms frame, preferably in every 10 ms frame.

26. The base station arrangement of claim 17, wherein the transmitter is arranged to transmit multiple redirected reference signals per time frame.

27. The base station arrangement of claim 17, wherein the radio access network uses WINNER technology, wherein the transmitter is arranged to transmit the redirected reference signal in the first part of a super-frame.

28. The base station arrangement of claim 17, wherein the uplink quality based frequency domain scheduling means is arranged to input the received channel quality to the scheduling algorithm for uplink quality based frequency domain scheduling in the time and/or in the frequency domain.

29. The base station arrangement of claim 28, wherein the uplink quality based frequency domain scheduling means further is arranged to input channel quality, based on the received regular reference signal, to the scheduling algorithm for uplink quality based frequency domain scheduling in the time and/or in the frequency domain.

30. The base station arrangement of claim 17, wherein the receiver further is arranged to receiving a regular uplink reference signal from the mobile terminal, and wherein the base station arrangement comprises an estimation unit for estimating the uplink channel quality, based on the received regular reference signal.

31. The base station arrangement of claim 17, wherein the transmitter further is arranged to transmit an uplink control message on a downlink channel to the mobile terminal based on the performed uplink quality based frequency domain scheduling.

32. A method for managing uplink channel estimation in a mobile terminal, the mobile terminal being comprised in a radio access network using Frequency Division Duplex, the radio access network comprising a number of cells, the mobile terminal being situated in a first cell of said number of cells, the mobile terminal is connectable to a network infrastructure via a base station associated with the first cell, the method comprising the steps of:

receiving a redirected reference signal on an uplink band from the base station, said redirected reference signal being intended for uplink channel estimation, wherein the mobile terminal knows the origin redirected reference signal transmitted by the base station;

estimating an uplink channel quality by estimating the received redirected reference signal and comparing the known origin redirected reference signal with the estimated received redirected reference signal;

transmitting a report to the base station, the report comprising the estimated uplink channel quality;

receiving a scheduling control message from the base station responsive to the report, the scheduling control message scheduling the mobile station for use of resources assigned based on the estimated uplink channel quality; and

transmitting data using the assigned resources.

33. The method of claim 32, wherein the step of comparing is based on the amplitude and/or phase of the origin redirected reference signal and received redirected reference signal.

34. The method of claim 32, comprising the further step of:

determining adaptive modulation and/or coding scheme and/or which power to use, and/or antenna weights, based on the estimated uplink channel quality.

35. A computer program product for managing uplink channel estimation in a mobile terminal, comprising a non-transitory computer-readable medium encoded with computer program code, the code operable, when executed by a processor, to:

receive a redirected reference signal on an uplink band from the base station, said redirected reference signal being intended for uplink channel estimation, wherein the mobile terminal knows the origin redirected reference signal transmitted by the base station;

estimate an uplink channel quality by estimating the received redirected reference signal and comparing the known origin redirected reference signal with the estimated received redirected reference signal;

transmit a report to the base station, the report comprising the estimated uplink channel quality;

receive a scheduling control message from the base station responsive to the report, the scheduling control message scheduling the mobile station for use of resources assigned based on the estimated uplink channel quality ˜

and transmit data using the assigned resources.

36. An arrangement in a mobile terminal being comprised in a radio access network using Frequency Division Duplex, the radio access network comprising a number of cells, the mobile terminal being situated in a first cell of said number of cells, the mobile terminal is connectable to a network infrastructure via a base station associated with the first cell, the mobile station arrangement comprising:

a receiver for receiving a redirected reference signal, on the uplink band, from the base station, said redirected reference signal being intended for uplink channel estimation, wherein the mobile terminal knows the origin redirected reference signal transmitted by the base station;

an estimation unit arranged to estimate an uplink channel quality by estimating the received redirected reference signal and comparing the known origin redirected reference signal with the estimated received redirected reference signal; and

a transmitter arranged to transmit a report to the base station, the report comprising the estimated uplink channel quality,

wherein the receiver is further arranged to receive a scheduling control message from the base station responsive to the report, the scheduling control message scheduling the mobile station for use of resources assigned based on the estimated uplink channel quality; and

wherein the transmitter is further arranged to transmit data using the assigned resources.

37. The mobile terminal arrangement of claim 36, wherein the estimation unit further is arranged to make the comparing based on the amplitude and/or phase of the origin redirected reference signal and received redirected reference signal.

38. The mobile terminal arrangement of claim 36, further comprises a determination unit means for determining adaptive modulation and/or coding scheme and/or which power to use, and/or antenna weights, based on the estimated uplink channel quality.