Method and system for wireless communication networks using relaying

• US 20050014464A1
• Filed: 05/28/2004
• Published: 01/20/2005
• Est. Priority Date: 05/28/2003
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Larsson, Peter
• Application Number:
  US10/855,898
• Publication Number:
  US 20050014464A1
• Time in Patent Office: Days
• US Class Current: 455/11.100
• 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 7/15528 Control of operation parameters of a relay station to exploit the physical medium
• CPC Class Codes: H04B 7/15592 Adapting at the relay station communication parameters for supporting cooperative relaying, i.e. transmission of the same data via direct - and relayed path cooperative diversity H04B7/024
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/20 Repeater circuits; Relay circuits
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

The present invention relates to wireless networks using relaying. In the method according to the present invention of performing communication in a two-hop wireless communication network, a transmitter 210, a receiver 220 and at least one relay station 215 are engaged in a communication session. The relay station 215 forwards signals from a first link between the transmitter 210 and the relay station 215 to a second link between the relay stations 215 and the receiver 220. The forwarding performed by the at least one relay station 215 is adapted as a response to estimated radio channel characteristics of at least the first link. Preferably the forwarding is adapted as a response to estimated radio channel characteristics of both the first and second link.

Claims

1. A method of performing communication in a two-hop wireless communication network, wherein a transmitter, a receiver and at least one relay station are engaged in a communication session, and the relay station forwards signals from a first link between the transmitter and the relay station to a second link between the relay stations and the receiver, wherein the forwarding performed by the at least one relay station is adapted as a response to estimated radio channel characteristics of at least the first link.

2. The method according to claim 1, wherein the forwarding performed by the at least one relay station is adapted as a response to estimated radio channel characteristics of both the first and second link.

3. The method according to claim 1, wherein the communication session involves a plurality of relay stations and their respective forwarding is adapted based on a relative transmission parameter which is specific for each relay station and a common transmission parameter which is common to all relay stations.

4. The method according to claim 1, wherein the method comprises the steps of:

characterizing the radio paths of the first and second link by the use of pilots;

determine at least one relative transmission parameter at least partly based on both of the channel estimates of each relay stations paths of the first and second link;

determine at least one common transmission parameter based;

distributing at least said common transmission parameter to all relay station;

forwarding the signal from the first link on the second link, wherein the forwarded signal is adapted based on each relay stations relative transmission parameter and the common transmission parameter.

5. The method according to claim 1, wherein the adaptation of the transmitted signal comprises an adjustment of phase.

6. The method according to claim 1, wherein the adaptation of the transmitted signal comprises an adjustment of transmission power.

7. The method according to claim 1, wherein the adaptation of the transmitted signal comprises an adjustment of transmission power and phase.

8. The method according to claim 1, wherein the adaptation of the transmitted signal comprises an adjustment of parameters relating to diversity.

9. The method according to of claims 8, wherein the adaptation of the transmitted signal comprises an adjustment of parameters relating to delay diversity.

10. The method according to of claims 8, wherein the adaptation of the transmitted signal comprises an adjustment of parameters relating to space time coded diversity.

11. The method according to claim 1, wherein the step of using the relay station'"'"'s respective relative transmission parameter and the common transmission parameter(s) to adapt the subsequent transmissions on link 2, comprises to, on the reception of signal y_k, transmit the signal:

12. A relay station adapted for use in a two-hop wireless communication network, wherein the network comprises a transmitter, a receiver and at least one relay station, wherein the relay station is adapted to forwarding signals from a first link between the transmitter and the relay station to a second link between the relay stations and the receiver wherein the relay station is provided with means for adapting the forwarding based on a characterization of at least the first link.

14. The relay station according to claim 14, wherein the relay station is further provided with means for performing channel characterization and means for determining relative transmission parameters based on the channel characterization, and the forwarding is at least partly based on said relative transmission parameters.

13. The relay station according to claim 14, wherein the relay station adapt the forwarding as a response to estimated radio channel characteristics of both the first and second link.

15. The relay station according to claim 15, wherein the relay station is further provided with means for receiving a common transmission parameter, and the forwarding is at least partly based on said relative transmission parameters and said common transmission parameter

16. A system adapted for communication in a two-hop wireless communication network, wherein the network comprises a transmitter, a receiver and at least one relay station, wherein the relay station is adapted to forwarding signals from a first link between the transmitter and the relay station to a second link between the relay stations and the receiver wherein the relay station uses characterization of at least the first link for the forwarding on the second link.

17. The system according to claim 16, wherein the relay station adapt the forwarding as a response to estimated radio channel characteristics of both the first and second link.

19. The system according to claim 17, wherein the system is provided with means for determining a common transmission parameter which is based on the total communication quality between the transmitter and the receiver, and the relay station is further provided with means for receiving the common transmission parameter and the forwarding on the second link is at least partly based on said relative transmission parameters and said common transmission parameter.

18. The system according to claim 18, wherein the relay station is further provided with means for performing channel characterization and means for determining relative transmission parameters based on channel characterization and the forwarding is at least partly based on said relative transmission parameters.

20. A receiver adapted for use in a two-hop wireless communication network, wherein the network comprises a transmitter, the receiver and at least one relay station, wherein the relay station is adapted to forwarding signals from a first link between the transmitter and the relay station to a second link between the relay stations and the receiver, wherein the receiver is provided with means for determining at least one relative transmission parameter which is based on a characterization of at least the first link, and means for distributing said relative transmission parameter to the relay station.

21. The receiver according to claim 20, wherein the determining means are adapted to determine a plurality of relative transmission parameter, one for each relay station which are engaged in the communication session.

22. The receiver according to claim 20, wherein the relative transmission parameter is based on characterisations of both the first and second link.

23. The receiver according to claim 20, wherein the receiver i further provided with means for determining a common transmission parameter which is based on the total communication quality between the transmitter and the receiver.

24. A base station adapted for use in a two-hop wireless communication network, comprising a receiver according to claim 20.

25. A mobile station adapted for use in a two-hop wireless communication network, comprising a receiver according to claim 20.