Method to achieve diversity in a communication network

• US 20020115409A1
• Filed: 02/21/2001
• Published: 08/22/2002
• Est. Priority Date: 02/21/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Khayrallah, Ali S.
• Granted Patent: US 7,113,745 B2
• Time in Patent Office: Days
• US Class Current: 455/41.2
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/06 at the transmitting station
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 52/04 TPC

Abstract

A method of wirelessly communicating between units comprises using at least two repeaters between a transmit unit and a receive unit. The repeaters enable a diversity scheme to be emulated.

Claims

1. A method of communicating a message between two stations, comprising:

receiving said message transmitted from a first station at at least two repeaters, said message transmitted over a wireless communication channel; and

retransmitting said message from said at least two repeaters to a second station such that spatial diversity is created between said first station and said second station.

2. The method of claim 1 further comprising forming a network comprising at least said first station, said second station, and said at least two repeaters.

3. The method of claim 2 wherein forming a network comprising at least said first station, said second station, and said at least two repeaters comprises forming an ad hoc network.

4. The method of claim 2 wherein forming a network comprising at least said first station, said second station, and said at least two repeaters comprises forming a network with at least two fixed repeaters.

5. The method of claim 1 further comprising transmitting said message from said first station to said at least two repeaters.

6. The method of claim 5 wherein transmitting said message from said first station to said at least two repeaters comprises encoding said message into at least two distinct signals.

7. The method of claim 6 further comprising transmitting a first one of said at least two distinct signals to a first one of said at least two repeaters.

8. The method of claim 7 further comprising transmitting a second one of said at least two distinct signals to a second one of said at least two repeaters.

9. The method of claim 1 further comprising receiving said message at said second station from said at least two repeaters.

10. The method of claim 9 wherein receiving said message at said second station from said at least two repeaters comprises receiving distinct signals on different frequencies.

11. The method of claim 9 wherein receiving said message at said second station from said at least two repeaters comprises receiving distinct signals at different times.

12. The method of claim 1 wherein retransmitting said message from said at least two repeaters to a second station such that spatial diversity is created between said first station and said second station comprises retransmitting the message such that frequency transmit diversity is created.

13. The method of claim 1 wherein retransmitting said message from said at least two repeaters to a second station such that spatial diversity is created between said first station and said second station comprises retransmitting the signal such that time transmit diversity is created.

15. The method of claim 14 wherein transmitting a message from a first station to at least two repeaters comprises transmitting a message from a first station using a single antenna.

16. The method of claim 15 wherein transmitting a message from a first station using a single antenna comprises repeating transmission of said message to each of the at least two repeaters.

17. The method of claim 14 wherein transmitting a message from a first station to at least two repeaters comprises simultaneously transmitting a signal on two different frequency channels.

18. The method of claim 14 further comprising forming a network comprising said first station, said second station, and said at least two repeaters.

19. The method of claim 18 wherein forming a network comprising said first station, said second station, and said at least two repeaters comprises forming an ad hoc network.

20. The method of claim 18 wherein comprising said first station, said second station, and said at least two repeaters comprises forming a network with at least two fixed repeaters.

21. The method of claim 14 wherein receiving said at least two distinct signals at said second station comprises receiving, using a single antenna, each of said at least two distinct signals at said second station.

14. A method of communicating, comprising:

transmitting a message from a first station to at least two repeaters;

receiving said message at said at least two repeaters;

retransmitting said message, via at least two distinct signals, one of said at least two distinct signals transmitted from each of said at least two repeaters to a second station;

receiving said at least two distinct signals at said second station;

combining said at least two distinct signals to reconstruct said message.

22. A transmitter comprising:

a controller adapted to encode a message into at least two distinct signals; and

a transmit antenna to transmit a first one of said at least two distinct signals to a first one of said at least two repeaters and a second one of said at least two distinct signals to a second one of said at least two repeaters.

23. The transmitter of claim 22 wherein said transmit antenna comprises the sole antenna used at an operative frequency band.

24. The transmitter of claim 22 wherein said controller is adapted to transmit identical signals to the at least a two repeaters sequentially.

25. The transmitter of claim 22 wherein said controller is adapted to transmit said at least two distinct signals to the at least two repeaters simultaneously at different frequencies.

27. The communication system of claim 26 wherein said transmitter transmits to said at two repeaters using just said first transmit antenna.

28. The communication system of claim 27 wherein said transmitter transmits a signal containing said message to a first one of said at least two repeaters and then transmits said signal containing said message to a second one of said at least two repeaters.

29. The communication system of claim 26 wherein said transmitter transmits said message to said at two repeaters simultaneously on two different frequency channels.

30. The communication system of claim 26 wherein each of said at least two repeaters is spaced from one another.

31. The communication system of claim 26 wherein said system is formed on an ad hoc basis.

32. The communication system of claim 26 wherein said repeaters are fixed repeaters.

26. A communication system, comprising:

a transmitter comprising a first transmit antenna operative in a first frequency band and operative to transmit a message;

at least two repeaters operating in said first frequency band, said at least two repeaters operative to receive said message from said transmitter and to retransmit said message;

a receiver comprising a first receive antenna operating in said first frequency band to receive said retransmitted message from each of said at least two repeaters.

33. An ad-hoc wireless communication system, comprising:

a transmit unit using a single transmit antenna;

a plurality of intermediate units;

a receive unit using a single receive antenna; and

said intermediate units serving as repeaters to pass a message between said transmit unit and said receive unit thereby creating an effective transmit diversity wireless communication system.

34. The wireless communication system of claim 33 wherein said transmit unit processes said message into at least two signals, each of which is sent to different ones of said plurality of intermediate units.

35. The wireless communication system of claim 34 wherein said transmit unit transmits said at least two signals simultaneously on different frequencies.

36. The wireless communication system of claim 34 wherein said transmit unit transmits said at least two signals sequentially on a single frequency channel.

37. The wireless communication system of claim 34 wherein respective ones of said intermediate units retransmit respective ones of said at least two signals to said receive unit.

38. The wireless communication system of claim 37 wherein said intermediate units retransmit said at least two signals on a common channel at the same time.

39. The wireless communication system of claim 37 wherein said intermediate units retransmit said at least two signals twice at different times.

40. The wireless communication system of claim 39 wherein said intermediate units retransmit said at least two signals simultaneously on a first common frequency channel and again on a second common channel.

41. The wireless communication system of claim 39 wherein said intermediate units retransmit said at least two signals sequentially on a first common frequency channel at a first time and again on said first common frequency channel at a second time.

42. The wireless communication system of claim 37 wherein said intermediate units retransmit said at least two signals on different frequencies.

43. The wireless communication system of claim 37 wherein said intermediate units retransmit said at least two signals at different times.

44. The wireless communication system of claim 33 further comprising a power control feedback loop.

45. The wireless communication system of claim 44 wherein said power control feedback loop exists between said transmit unit and said plurality of intermediate units.

46. The wireless communication system of claim 44 wherein said power control feedback loop exists between said plurality of intermediate units and said receive unit.