Apparatus and method for transmitting and receiving forward channel quality information in a mobile communication system

• US 20030054847A1
• Filed: 08/29/2002
• Published: 03/20/2003
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Youn-Sun, Kim, Dong-Hee, Kwon, Hwan-Joon, Choi, Ho-Kyu, Jang, Jae-Sung
• Granted Patent: US 7,499,721 B2
• Time in Patent Office: Days
• US Class Current: 455/517
• CPC Class Codes: H04B 17/26 using historical data, averaging values or statistics
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal

Abstract

An apparatus and method for transmitting and receiving forward channel quality information between a base station and a mobile station in a CDMA mobile communication system supporting multimedia service including voice and data services. The mobile station transmits an absolute value symbol in at least one time slot selected from a plurality of time slots, and a relative value symbol in one of the remaining time slots. The absolute value symbol represents the signal strength of the forward channel in the at least one time slot corresponding to the selected time slot, and the relative value symbol represents a change in the signal strength of the forward channel between the at least one time slot corresponding to the one remaining time slot and the signal strength of the forward channel in a previous time slot.

Claims

1. A method of measuring quality of a forward channel received from a base station and reporting the quality measurement to the base station in a mobile station, comprising the steps of:

measuring signal strengths of the forward channel in a plurality of time slots;

transmitting an absolute value symbol in at least one time slot selected from the plurality of time slots, the absolute value symbol representing the signal strength of the forward channel; and

transmitting a relative value symbol in at least one remaining time slots other than the time slot selected to transmit the absolute value symbol, the relative value symbol representing a change from the signal strength of the forward channel in a previous time slot.

2. The method of claim 1, wherein the relative value symbol is transmitted at a transmission power level less than the transmission power level of the absolute value symbol.

3. The method of claim 1, wherein the relative value symbol has less bits than the absolute value symbol.

4. The method of claim 1, wherein the relative value symbol represents an increase or a decrease in the signal strength of the forward channel in the at least one time slot corresponding to the one remaining time slot against the signal strength of the forward channel in the previous time slot.

5. The method of claim 1, wherein the relative value symbol represents an increase, no change, or a decrease in the signal strength of the forward channel in the at least one time slot corresponding to the one remaining time slot against the signal strength of the forward channel in the previous time slot.

6. The method of claim 1, wherein the selected time slot for transmitting the absolute value symbol is different from time slots transmitting absolute value symbols from other mobile stations.

7. The method of claim 1, wherein the selected time slot satisfies

(T−

N−

X) MODINT=0

where T is system time counted in the unit of slots, INT is a transmission interval at which an absolute value symbol is transmitted, N is a parameter that determines a slot for transmitting the absolute value symbol in the transmission interval INT, and X is a parameter unique to the mobile station.

8. The method of claim 1, wherein the absolute value symbol is transmitted in two successive time slots.

9. The method of claim 1, wherein the relative value symbol transmitting step comprises the steps of:

searching for the level of the signal strength measured in the one remaining time slot in a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits;

generating the relative value symbol representing the result of comparing the signal strength level of the one remaining time slot with the signal strength level of the previous time slot; and

encoding the relative value symbol prior to transmission.

10. The method of claim 1, wherein the relative value symbol transmitting step comprises the steps of:

generating the relative value symbol representing the result of comparing the signal strength of the one remaining time slot with the signal strength of the previous time slot; and

encoding the relative value symbol prior to transmission.

11. The method of claim 10, wherein in the encoding step, the relative value symbol is encoded to one of a plurality of predetermined code sequences having a maximum difference there between.

12. The method of claim 11, wherein one of the code sequences has all 0s and the other code sequence has all 1s.

13. The method of claim 1, wherein the absolute value symbol transmitting step comprises the steps of:

generating the absolute value symbol representing the measured signal strength of the forward channel in the selected time slot referring to a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits; and

encoding the absolute value symbol prior to transmission.

14. A method of measuring quality of a forward channel received from a base station and reporting the quality measurement to the, base station in a mobile station, comprising the steps of:

measuring signal strengths of the forward channel in a plurality of time slots;

transmitting an absolute value symbol in at least one time slot selected from the plurality of time slots, the absolute value symbol representing the measured signal strength of the forward channel, and storing the measured signal strength; and

transmitting a relative value symbol in at least one remaining time slot other than the at least one time slot selected to transmit the absolute value symbol, the relative value symbol representing a change from the stored signal strength of the forward channel in a previous time slot, updating the signal strength of the previous time slot according to what the relative value symbol represents, and storing the updated signal strength.

15. The method of claim 14, wherein the relative value symbol is transmitted at a transmission power level less than the transmission power level of the absolute value symbol.

16. The method of claim 14, wherein the relative value symbol has less bits than the absolute value symbol.

17. The method of claim 14, wherein the relative value symbol represents an increase or a decrease in the signal strength of the forward channel in the at least one time slot corresponding to the one remaining time slot against the stored signal strength of the forward channel in the previous time slot.

18. The method of claim 14, wherein the relative value symbol represents an increase, no change, or a decrease in the signal strength of the forward channel in the at least one time slot corresponding to the one remaining time slot against the stored signal strength of the forward channel in the previous time slot.

19. The method of claim 14, wherein the selected time slot for transmitting the absolute value symbol is different from time slots transmitting absolute value symbols from other mobile stations.

20. The method of claim 14, wherein the selected time slot satisfies

(T−

N−

X) MOD INT=0

where T is system time counted in the unit of slots, INT is a transmission interval at which an absolute value symbol is transmitted, N is a parameter that determines a slot for transmitting the absolute value symbol in the transmission interval INT, and X is a parameter unique to the mobile station.

21. The method of claim 14, wherein the absolute value symbol is transmitted in two successive time slots.

22. The method of claim 14, wherein the relative value symbol transmitting step comprises the steps of:

generating the relative value symbol representing the result of comparing the signal strength level of the one remaining time slot with the stored signal strength level of the previous time slot;

encoding the relative value symbol; and

increasing or decreasing the stored signal strength of the previous time slot by a predetermined unit according to what the relative value symbol represents.

23. The method of claim 22, wherein the predetermined unit is set beforehand between the base station and the mobile station.

24. The method of claim 22, wherein in the encoding step, the relative value symbol is encoded to one of a plurality of predetermined code sequences having a maximum difference there between.

25. The method of claim 24, wherein one of the code sequences has all 0s and the other code sequence has all 1s.

26. The method of claim 14, wherein the absolute value symbol transmitting step comprises the steps of:

generating the absolute value symbol representing the measured signal strength of the forward channel in the selected time slot referring to a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits;

encoding the absolute value symbol; and

storing the signal strength corresponding to the absolute value symbol.

27. A method of receiving forward channel quality information from a mobile station in a base station, comprising the steps of:

(1) receiving an absolute value symbol in at least one time slot selected from a plurality of time slots;

(2) calculating the signal strength of the selected time slot according to the absolute value symbol;

(3) receiving a relative value symbol in at least one remaining time slot other than the at least one time slot selected to transmit the absolute value symbol; and

(4) calculating the signal strength of the at least one remaining time slot by updating the signal strength of a previous time slot according to what the relative value symbol represents.

28. The method of claim 27, wherein the selected time slot satisfies

(T−

N−

X) MOD INT=0

where T is system time counted in the unit of slots, INT is a transmission interval at which an absolute value symbol is transmitted, N is a parameter that determines a slot for transmitting the absolute value symbol in the transmission interval INT, and X is a parameter unique to the mobile station.

29. The method of claim 27, wherein in step (2) the signal strength level corresponding to the absolute value symbol is searched for in a mapping table in which a plurality of predetermined signal strength levels are mapped to symbols each having a predetermined number of bits.

30. The method of claim 27, wherein in step (4) the signal strength of the previous time slot is increased or decreased by one level according to what the relative value symbol represents referring to a mapping table in which a plurality of predetermined signal strength levels are mapped to symbols each having a predetermined number of bits.

31. The method of claim 27, wherein in step (4) the signal strength of the previous time slot is increased or decreased by a predetermined unit according to what the relative value symbol represents.

32. The method of claim 31, wherein the predetermined unit is set beforehand between the base station and the mobile station.

33. An apparatus for measuring quality of a forward channel received from a base station and reporting the quality measurement to the base station in a mobile station, comprising:

a symbol generator for generating an absolute value symbol in at least one time slot selected from a plurality of time slots and generating a relative value symbol in at least one remaining time slot other than the at least one time slot selected to transmit the absolute value symbol, the absolute value symbol representing the signal strength of the forward channel , and the relative value symbol representing a change from the signal strength of the forward channel in a previous time slot; and

an encoding unit for encoding the absolute value symbol and the relative value symbol.

34. The apparatus of claim 33, further comprising a transmitter for transmitting the encoded relative value symbol at a transmission power level less than the transmission power level of the encoded absolute value symbol.

35. The apparatus of claim 33, wherein the selected time slot for transmitting the absolute value symbol is different from time slots transmitting absolute value symbols from other mobile stations.

36. The apparatus of claim 33, wherein the selected time slot satisfies

(T−

N−

X) MOD INT=0

where T is system time counted in the unit of slots, INT is a transmission interval at which an absolute value symbol is transmitted, N is a parameter that determines a slot for transmitting the absolute value symbol in the transmission interval INT, and X is a parameter unique to the mobile station.

37. The apparatus of claim 33, wherein the absolute value symbol is transmitted in two successive time slots.

38. The apparatus of claim 33, wherein the symbol generator searches for the level of the signal strength measured in the at least one remaining time slot in a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits, and generates the relative value symbol representing the result of comparing the signal strength level of the at least one remaining time slot with the signal strength level of the previous time slot.

39. The apparatus of claim 33, wherein the symbol generator generates the relative value symbol representing the result of comparing the signal strength level of the at least one remaining time slot with the signal strength level of the previous time slot.

40. The apparatus of claim 33, wherein the relative value symbol represents an increase or a decrease in the signal strength of the at least one time slot corresponding to the one remaining time slot against the signal strength level of the previous time slot.

41. The apparatus of claim 33, wherein the relative value symbol represents an increase, no change, or a decrease in the signal strength of the at least one time slot corresponding to the one remaining time slot against the signal strength level of the previous time slot.

42. The apparatus of claim 33, wherein the symbol generator generates the absolute value symbol representing the measured signal strength of the forward channel in the selected time slot referring to a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits.

43. The apparatus of claim 33, wherein the symbol generator comprises:

a first device for generating the absolute value symbol representing the measured signal strength of the forward channel in the selected time slot and storing the measured signal strength; and

a second device for generating the relative value symbol representing a change against the stored signal strength of the forward channel in the previous time slot, updating the signal strength of the previous time slot according to what the relative value symbol represents, and storing the updated signal strength.

44. The apparatus of claim 43, wherein the first device generates the absolute value symbol representing the measured signal strength of the forward channel in the selected time slot referring to a mapping table mapping a plurality of predetermined signal strength levels to symbols each having a predetermined number of bits, and stores the signal strength.

45. The apparatus of claim 43, wherein the second device generates the relative value symbol representing the result of comparing the signal strength level of the at least one remaining time slot with the signal strength level of the previous time slot, and increases or decreases the stored signal strength of the previous time slot by a predetermined unit according to what the relative value symbol represents.

46. The apparatus of claim 33, wherein the encoding unit comprises an encoder for encoding the absolute value symbol and the relative value symbol at the same code rate.

47. The apparatus of claim 46, wherein the encoder encodes the relative value symbol to one of a plurality of predetermined code sequences having a maximum difference there between.

48. The apparatus of claim 47, wherein the code sequence has all 0s or all 1s.

49. The apparatus of clam 33, wherein the encoding unit comprises:

a first encoder for encoding the absolute value symbol at a first code rate according to the number of bits of the absolute value symbol; and

a second encoder for encoding the relative value symbol at a second code rate according to the number of bits of the relative value symbol.

50. The apparatus of claim 49, wherein the number of bits of the relative value symbol is less than the number of bits of the absolute value symbol.

51. An apparatus for receiving forward channel quality information from a mobile station in a base station, comprising:

a receiver for receiving an absolute value symbol in at least one time slot selected from a plurality of time slots, and receiving a relative value symbol in at least one remaining time slot other than the at least one time slot selected to transmit the absolute value symbol; and

a symbol calculator for calculating the signal strength of the selected time slot according to the absolute value symbol, calculating the signal strength of the at least one remaining time slot by updating the signal strength of a previous time slot according to what the relative value symbol represents.

52. The apparatus of claim 51, wherein the selected time slot satisfies

(T−

N−

X) MOD INT=200

where T is system time counted in the unit of slots, INT is a transmission interval at which an absolute value symbol is transmitted, N is a parameter that determines a slot for transmitting the absolute value symbol in the transmission interval INT, and X is a parameter unique to the mobile station.

53. The apparatus of claim 51, wherein the symbol calculator searches for the signal strength level corresponding to the absolute value symbol in a mapping table in which a plurality of predetermined signal strength levels are mapped to symbols each having a predetermined number of bits.

54. The apparatus of claim 51, wherein the symbol calculator increases or decreases the signal strength of the previous time slot by one level according to what the relative value symbol represents referring to a mapping table in which a plurality of predetermined signal strength levels are mapped to symbols each having a predetermined number of bits.

55. The apparatus of claim 51, wherein the symbol calculator increases or decreases the signal strength of the previous time slot by a predetermined unit according to what the relative value symbol represents.

56. The apparatus of claim 55, wherein the predetermined unit is set beforehand between the base station and the mobile station.