Adaptive channel measurement reporting

• US 20070064772A1
• Filed: 12/19/2003
• Published: 03/22/2007
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wiberg, Niclas, Furuskar, Anders
• Granted Patent: US 8,036,327 B2
• Time in Patent Office: Days
• US Class Current: 375/144
• CPC Class Codes: H04B 17/20 of receivers
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0236 using estimation of the other symbols

Abstract

The present invention relates to a method, arrangements, and a message format for achieving an improved and adaptive reporting of measurements for a communication channel between a transmitter and a receiver unit. The invention achieves a message format for providing detailed channel information to a transmitter unit but requiring a minimized amount of transmission capacity. The receiver unit delivers preferably incremental updatings of the filter function, represented in the time- or frequency domain, of the entire channel between transmitter and receiver. For this purpose the channel representing function is divided into a number of sub-functions, a function of which corresponding to the true channel filter function, and whereof the various sub-functions contain channel information of a ranked degree of significance.

Claims

1-25. -25. (canceled)

26. A method in a receiver unit to receive communication signals from a transmitter unit via a multi-path channel, said method comprising the steps of:

estimating parameters of a channel filter function of said channel from said received communication signals from the transmitter unit;

sub-dividing the channel filter function into two or more parts, a function of which representing an approximation of the estimated full channel filter function;

representing the complex parameters of at least a selection of said parts of the channel filter function as actual parameter values, or as incremental values indicating the difference to a reference value; and

,

composing a channel measurement message to be transmitted to the transmitter unit of a portion including said parameter representations and a portion indicating the manner of representing said parameters.

27. The method according to claim 26, wherein said function performs a summing of the sub-divided parts of the channel filter function.

28. The method according to claim 26, wherein the sub-divided parts of the channel filter function comprise channel information of a ranked degree of significance.

29. The method according to claim 26, wherein the channel filter function is represented as a channel impulse response in the time-domain.

30. The method according to claim 29, wherein the complex parameters of the channel impulse response are reproduced as amplitude and phase values.

31. The method according to claim 29, wherein the primary sub-divided filter function includes a representation of one or more of the most significant channel components.

32. The method according to claim 31, wherein the most significant channel component is the component having the shortest delay.

33. The method according to claim 26, wherein the channel filter function is represented as a channel frequency response in the frequency-domain.

34. The method according to claim 33, wherein a complex parameter of the channel frequency response is reproduced at least as an amplitude value and optionally by an additional phase value.

35. The method according to claim 26, wherein the complex parameters of said parts of the channel filter function are represented by their actual values in case of a significant change compared to a previous reference value.

36. The method according to claim 35, wherein the reference value corresponds to a previous channel parameter representation.

37. The method according to claim 35, wherein the reference value corresponds to a modelled estimate of the channel filter function.

38. The method according to claim 37, wherein the modelled estimate is a interpolation of the channel filter function from the complex parameters of the channel filter function.

39. The method according to claim 37, wherein said modelled estimate of the channel filter function has been received by the transmitter unit.

40. A message format for representing a channel filter function, comprising:

a first portion representing each of the complex parameters of the sub-divided parts of the channel filter function by at least an amplitude value and optionally by an additional phase value.

41. The message format according to claim 40, further comprising a second portion comprising an indication of the manner of representing said complex parameters including at least an indication α

denoting the influence of previously measured parameter values.

42. The message format according to claim 41, wherein α

is a binary value.

43. The message format according to claim 41, wherein said second portion comprises an indication of the domain within which the channel filter function is represented.

44. The message format according to claim 41, wherein said second portion includes an indication of the sampling period for the complex parameter values of the sub-divided parts of the channel filter function.

45. The message format according to claim 40, wherein said representations of the complex parameters of the sub-divided parts of the channel filter function are associated to an indication (321) of a time or frequency instance.

46. An apparatus for processing communication signals received via a multipath channel, comprising:

means for estimating parameters of a channel filter function of said channel from said received communication signals from the transmitter unit;

means for sub-dividing the channel filter function into two or more parts, a function of which representing the estimated full channel filter function;

means for representing the complex parameters of at least a selection of the sub-divided channel filter function as actual parameter values, or as incremental values indicating the difference to a reference value; and

,

means for composing a channel measurement message to be transmitted to the transmitter unit including said set of parameter representations and a header field indicating the manner of representing said parameters.

47. The apparatus according to claim 46, which is integrated in a mobile user equipment.

48. An apparatus in a transmitter unit for transmitting communication signals to a receiver unit, comprising means for indicating a requested representation of the content of a channel measurement message to be transmitted to the transmitter unit in terms of the manner of said representation.

49. The apparatus according to claim 48, further including means for indicating at least an amplitude value and optionally an additional phase value of the complex parameters of a modelled estimate of sub-divided parts of a channel filter function as actual parameter values, or as incremental values indicating the difference to a reference value.

50. The apparatus according to claim 48, which is integrated in a radio base station.