Power control apparatus, and an associated method, for TDMA transmitter

• US 6,072,792 A
• Filed: 07/03/1997
• Issued: 06/06/2000
• Est. Priority Date: 07/03/1997
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Ostman, Thomas, Hagerman, Bo, Mazur, Sara
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US08/887,726
• Time in Patent Office: 1,069 Days
• Field of Search: 370/330, 370/337, 370/442, 370/528, 370/200, 370/201, 370/252, 370/335, 455/88, 455/69, 455/522, 455/54, 455/70
• US Class Current: 370/345
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Power control apparatus and an associated method for a transmitting station operable in a TDMA communication system. The transmitting station includes transmitter branches for communicating communication signal bursts during selected time slots. Communication signal bursts transmitted upon adjacent time slots partially overlap so that a receiving station is able to extract information from a communication signal burst transmitted upon an adjacent time slot.

Claims

1. In a transmitting station operable in a TDMA communication system at least to communicate a first communication signal burst to a first remote station during a predetermined time slot, and at least a second communication signal burst to at least a second remote station during a predetermined time slot, an improvement of power control apparatus for selectively controlling power levels at which the first communication signal burst and the at least the second communication signal burst are communicated, said power control apparatus comprising:

a first transmitter branch to which one of the first communication signal burst and the at least the second communication signal burst is applied, said first transmitter branch for transmitting the signal burst received thereat at a first selected power level to the first remote station during a first time slot of a TDMA frame; and

at least a second transmitter branch to which at least one of the first communication signal burst and the at least the second communication signal burst is applied, said second transmitter branch for transmitting the communication signal burst received thereat at a second selected power level different from the first power level, the communication signal burst transmitted by said second transmitter branch to the second remote station and transmitted for at least a portion of a time slot in the TDMA frame other than the first time slot, said communication signal burst transmitted by said first transmitter branch and by said second transmitter branch being transmitted at the same carrier frequency.

2. The power control apparatus of claim 1 wherein the signal burst applied to said first transmitter branch and the signal burst applied to said second transmitter branch are both formed of the first communication signal burst.

3. The power control apparatus of claim 2 wherein transmission of the first communication signal by said first transmitter branch is offset in time relative to, and overlapping with, transmission of the first communication signal by said second transmitter branch.

4. The power control apparatus of claim 3 wherein the first communication signal comprises a plurality of symbols and wherein the offset in time by which the first communication signal transmitted by said first transmitter branch is offset from the first communication signal transmitted by said second transmitter by an offset less than a selected number of symbols of the plurality of symbols.

5. The power control apparatus of claim 3 further comprising a delay element coupled to receive the first communication signal, said delay element for introducing the offset between the first communication signal transmitted by said first and second signal branches, respectively.

6. The power control apparatus of claim 1 wherein said first transmitter branch further comprises a first amplifier coupled to receive the one of the first communication signal burst and the at least the second communication signal burst, said first amplifier for amplifying the signal burst received thereat to be of the first selected power level.

7. The power control apparatus of claim 1 wherein said second transmitter branch further comprises a second amplifier coupled to receive the one of the first communication signal burst and the at least the second communication signal burst, said second amplifier for amplifying the signal burst received thereat to be of the second selected power level.

8. The power control apparatus of claim 1 wherein said first transmitter branch is allocated for communicating the first communication signal burst to the first remote station during the first time slot, wherein said second transmitter branch is allocated for communicating the second communication signal to the second remote station during a second time slot, and wherein said second communication signal transmitted by said second transmitter branch is transmitted during both the second time slot and a portion of the first time slot.

9. The power control apparatus of claim 8 wherein the portion of the first time slot during which the second communication signal burst is transmitted is of a length of at least great enough to permit the second remote station to extract information therefrom during the first time slot.

10. The power control apparatus of claim 1 wherein the total power level at which the first and second communication signal bursts are transmitted by said first and second transmitter branches, respectively, is substantially constant.

11. The power control apparatus of claim 1 further comprising a power level controller coupled to said first transmitter branch and to said at least the second transmitter branch, said power level controller for independently controlling selection of the first selected power level and the second selected power level at which the communication signal bursts transmitted by said first transmitter branch and said second transmitter branches, respectively, are transmitted.

12. The power control apparatus of claim 1 wherein the transmitting station is operable to transmit a plurality of communication signal bursts to a plurality of remote stations and wherein the first transmitter branch and the at least the second transmitter branch together transmit each of the first communication signal burst and the plurality of communication signal bursts.

13. The power control apparatus of claim 12 further comprising a scheduler for scheduling which of the communication signal bursts are transmitted by said first transmitter branch and said second transmitter branch.

14. The power control apparatus of claim 1 further comprising at least one antenna assembly coupled to at least one of said first transmitter branch and said at least the second transmitter branch, said antenna assembly capable of selectively forming directional antenna beam patterns.

15. The power control apparatus of claim 14 wherein said at least one antenna assembly comprises a first antenna assembly coupled to said first transmitter branch and a second antenna assembly coupled to said second transmitter branch, said first and second antenna assemblies together being operable to create spatial antenna diversity.

16. The power control apparatus of claim 14 wherein said at least one antenna assembly comprises a first antenna assembly coupled to said first transmitter branch and a second antenna assembly coupled to said second transmitter branch, said first and second antenna assemblies together being operable to create polarization antenna diversity.

17. The power control apparatus of claim 16 wherein said first and second antenna assemblies are together further operable to create spatial antenna diversity.

18. The power control apparatus of claim 16 wherein said first and second antenna assemblies are further capable of selectively forming directional antenna beam patterns.

19. The power control apparatus of claim 14 wherein said at least one antenna assembly comprises at least one antenna array formed of a plurality of antenna elements.

20. The power control apparatus of claim 19 wherein said at least one antenna assembly is further operable to create polarization antenna diversity.

21. The power control apparatus of claim 19 wherein said at least one antenna assembly is further operable to create spatial antenna diversity.

23. The power control apparatus of claim 1, wherein:

the communication signal burst transmitted by the first transmitter branch is an information-bearing signal burst; and

the communication signal burst transmitted by the second transmitter branch is an information-bearing signal burst.

24. The power control apparatus of claim 1, wherein the communication signal burst transmitted by the first transmitter branch and the communication signal burst transmitted by the second transmitter branch are transmitted in adjacent time slots.

25. The power control apparatus of claim 1, wherein the communication signal burst transmitted by the first transmitter branch and the communication signal burst transmitted by the second transmitter branch are transmitted in the same TDMA frame.

26. The power control apparatus of claim 1, wherein the transmission of the communication signal burst by the first transmitter branch and the transmission of the communication signal burst by the second transmitter branch partially overlap in time.

22. A method for selectively controlling power levels at which a first communication signal burst and at least a second communication signal burst are communicated by a transmitting station operable in a TDMA communication system at least to communicate the first communication signal burst to a first remote station during a first time slot, and the at least the second communication signal burst to at least a second remote station during at least a second time slot, said method comprising:

applying to a first transmitter branch one of the first communication signal burst and the at least the second communication signal burst and transmitting the signal burst applied thereto at a first selected power level to the first remote station; and

applying to at least a second transmitter branch at least one of the first communication signal burst and the at least the second communication signal burst and transmitting the communication signal burst applied thereto at a second selected power level that is different from the first power level to the second remote station using the same carrier frequency as the carrier frequency at which the first communication signal burst is transmitted, the communication signal burst transmitted by the second transmitter branch transmitted for at least a portion of a time slot in a TDMA frame other than the time slot during which the first transmitter branch transmits the signal burst received during said first step of applying to the first transmitter branch.

27. The method of claim 22, wherein

the communication signal burst transmitted by the first transmitter branch is an information-bearing signal burst;

and

the communication signal burst transmitted by the second transmitter branch is an information-bearing signal burst.

28. The method of claim 22, wherein the communication signal burst transmitted by the first transmitter branch and the communication signal burst transmitted by the second transmitter branch are transmitted in adjacent time slots.

29. The method of claim 22, wherein the communication signal burst transmitted by the first transmitter branch and the communication signal burst transmitted by the second transmitter branch are transmitted in the same frame.

30. The method of claim 22, wherein the transmission of the communication signal burst by the first transmitter branch and the transmission of the communication signal burst by the second transmitter branch partially overlap in time.

31. The method of claim 22, wherein the communication signal burst transmitted by the first transmitter branch and the communication signal burst transmitted by the second transmitter branch are identical signal bursts.

32. The method of claim 31, wherein the transmission of the communication signal burst transmitted by the second transmitter branch is delayed relative to the transmission of the communication signal burst transmitted by the first transmitter branch.

33. The method of claim 22, wherein said step of transmitting the signal burst applied to the second transmitter branch transmits at least one of the first communication signal burst and the at least the second communication signal burst during both the second time slot and a portion of the first time slot.

34. The method of claim 33, wherein the portion of the first time slot during which the second communication signal burst is transmitted by said second transmitter branch is of a length sufficient to permit the second remote station to extract information from the second communication signal burst during the first time slot.

35. The method of claim 22, further comprising the step of scheduling, prior to said steps of applying, communication signal bursts to be transmitted by the first and second transmitter branches.

36. A transmitting station for transmitting communication signal bursts to remote stations in a TDMA communication system, comprising:

a first transmitter branch capable of transmitting a communication signal burst during a predetermined time slot;

a second transmitter branch capable of transmitting a communication signal burst during a predetermined time slot;

said first transmitter branch scheduled to transmit a communication signal burst at a first transmission power level during a first time slot, said first transmitter branch scheduled to transmit a communication signal burst at a second transmission power level during a period of time that is timewise adjacent said first time slot, wherein said second transmission power level differs from said first transmission power level; and

said second transmitter branch scheduled to transmit a communication signal burst at said first transmission power level during said period of time, to permit the remote station assigned to said first time slot to extract information transmitted by said second transmitter branch during said period of time.

37. The apparatus of claim 36, wherein said communication signal bursts transmitted by said first and said second transmitter branches are transmitted using the same carrier frequency.

38. The apparatus of claim 36, wherein said period of time comprises at least a portion of a second time slot.

39. The apparatus of claim 36, wherein said second transmitter branch transmits an information-bearing communication signal burst at said first transmission power level during a portion of said first time slot.

40. The apparatus of claim 36, wherein said second transmitter branch transmits an information-bearing communication signal burst at said second transmission power level during a portion of said period of time.

41. A method for communicating within a TDMA communications system, comprising the steps of:

a first transmitter branch transmitting a communication signal burst at a first transmission power level a first transmitter branch during a first time slot, said first transmission power level being required by a remote station assigned to said first time slot;

the first transmitter branch transmitting a communications signal burst at a second transmission power level during a period of time that is timewise adjacent from said first time slot; and

a second transmitter branch transmitting a communication signal burst at said first transmission power level during said period of time so that said remote station can extract information transmitted by said second transmitter branch during said period of time.

42. The method of claim 41, further comprising the step of:

said second transmitter branch transmitting a communication signal burst at said first transmission power level during at least a portion of said first time slot.

43. The method of claim 41, further comprising the step of:

said second transmitter branch transmitting a communication signal burst at said second transmission power level during a portion of said period of time.

44. The method of claim 41, wherein:

said period of time comprises a second time slot that is timewise adjacent said first time slot.

45. The method of claim 41, wherein:

said communication signals bursts transmitted during said steps of transmitting communication signal bursts from said first transmitter branch and said step of transmitting a communication signal burst from said second transmitter branch are transmitted at the same carrier frequency.