Systems And Methods For Forwarding A Multi-User RF Signal

• US 20110275313A1
• Filed: 01/19/2009
• Published: 11/10/2011
• Est. Priority Date: 01/19/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Frenger, Päl, Larsson, Peter, Johansson, Niklas, Baldemair, Robert
• Granted Patent: US 8,750,789 B2
• Time in Patent Office: Days
• US Class Current: 455/17
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation

Abstract

A dynamic frequency translating repeater operating in a mobile communications system is operable to receive a multi-user signal and perform time-varying and user-specific frequency shifting in the repeater signal. The dynamic frequency translating repeater may further perform user subcarrier specific dynamic frequency translation. Different mobile stations may be allocated different frequency shift amounts based on the interference environments, resource allocations, and scheduling constraints particular to each mobile station.

Claims

1. A dynamic frequency translating repeater, said repeater comprising:

a receiver operable to receive a multi-user signal comprising a first user signal occupying a first spectrum and a second user signal occupying a second spectrum;

a first frequency shifter dynamically configurable to frequency shift the first spectrum by a first amount to produce a shifted first user signal, based on received first user information;

a second frequency shifter dynamically configurable to frequency shift the second spectrum by a second amount to produce a shifted second user signal, based on received second user information, wherein the first amount is not equal to the second amount;

a signal combiner configured to form a repeater signal comprising the shifted first user signal and the shifted second user signal; and

a transmitter operable to transmit the repeater signal.

2. The frequency translating repeater of claim 1 wherein the first amount is zero or the second amount is zero.

3. The frequency translating repeater of claim 1, wherein the multi-user signal is a downlink signal or is a superposition of a plurality of uplink signals.

4. The frequency translating repeater of claim 1, wherein the repeater is operable to receive, from one or more of a base station or other node, information specifying the first amount and the second amount.

5. The frequency translating repeater of claim 1, wherein the repeater is further operable to:

frequency shift a first portion of the first spectrum by a third amount to produce a first shifted first user signal;

frequency shift a second portion of the first spectrum by a fourth amount to produce a second shifted first user signal; and

form a repeater signal comprising the first and second shifted first user signals.

6. The frequency translating repeater according to claim 1, wherein the spectrum of the repeater signal overlaps with the spectrum of the multi-user signal.

7. The frequency translating repeater according to claim 1, further comprising:

a plurality of filters for filtering the multi-user signal to produce a corresponding plurality of signals; and

a plurality of modulators for modulating each of the corresponding plurality of signals with a complex exponential function of a different frequency.

8. The frequency translating repeater according to claim 1, further comprising a band pass filter for isolating the first user signal from the multi-user signal.

9. The frequency translating repeater according to claim 7, wherein a scaling factor is associated with at least one of the filters, said scaling factor specifying a power level for the transmission of the corresponding signal in the repeater signal, thereby enabling band-specific power control.

10. The frequency translating repeater according to claim 1, wherein the first frequency shifter is further configurable to frequency shift the first spectrum by the first amount at a first time to produce a shifted first user signal at a first time and to frequency shift the first spectrum by a fifth amount at a second time to produce a shifted first user signal at a second time, wherein the fifth amount is different than the first amount.

11. A method performed by a repeater in a mobile radio system, said method comprising:

receiving, at the repeater, a multi-user signal comprising a first user signal having a spectrum and a second user signal having a spectrum;

frequency shifting at least a portion of the spectrum of the first user signal by a first amount to produce a shifted first user signal, based on received first user information;

frequency shifting at least a portion of the spectrum of the second user signal by a second amount to produce a shifted second user signal, based on received second user information;

forming a repeater signal comprising the shifted first user signal and the shifted second user signal; and

transmitting the repeater signal;

wherein the first amount is not equal to the second amount.

12. The method according to claim 11 wherein the first amount is zero or the second amount is zero.

13. The method according to claim 11, wherein the multi-user signal is a downlink signal or is a superposition of a plurality of uplink signals.

14. The method according to claim 11, further comprising receiving, from one or more of a base station or other node, information specifying the first amount and the second amount.

15. The method of claim 11, wherein the step of frequency shifting the spectrum of the first user signal comprises:

frequency shifting a first portion of the spectrum of the first user signal by the first amount to produce a first shifted first user signal; and

frequency shifting a second portion of the spectrum of the first user signal by a third amount to produce a second shifted first user signal, wherein the third amount does not equal the first amount.

16. The method according to claim 11, wherein the spectrum of the repeater signal overlaps with the spectrum of the multi-user signal.

17. The method according to claim 11, further comprising:

using a plurality of filters to filter the multi-user signal to produce a corresponding plurality of signals; and

using a plurality of modulators to modulate each of the corresponding plurality of signals with a complex exponential function of a different frequency.

18. The method according to claim 11, wherein the first user signal is isolated from the multi-user signal by filtering the multi-user signal using a band pass filter.

19. The method according to claim 17, wherein a scaling factor is associated with at least one of the filters, said scaling factor specifying a power level for the transmission of the corresponding signal in the repeater signal, thereby enabling band-specific power control.

20. The method of claim 11, further comprising:

frequency shifting at least a portion of the spectrum of the first user signal by a fifth amount to produce a shifted first user signal at some point in time after frequency shifting at least a portion of the spectrum of the first user signal by the first amount, wherein the fifth amount is different than the first amount.

21. A frequency translating repeater, wherein the repeater is operable to:

receive a multi-user signal comprising a first user signal having a spectrum and a second user signal having a spectrum;

frequency shift the spectrum of the first user signal by a first amount to produce a shifted first user signal, based on received first user information;

frequency shift the spectrum of the second user signal by a second amount to produce a shifted second user signal, based on received second user information;

form a repeater signal comprising the shifted first user signal and the shifted second user signal; and

transmit the repeater signal;

wherein the first amount is not equal to the second amount.

22. The frequency translating repeater of claim 21 wherein the first amount is zero or the second amount is zero.

23. The frequency translating repeater of claim 21, wherein the multi-user signal is a downlink signal or is a superposition of a plurality of uplink signals.

24. The frequency translating repeater of claim 21, wherein the repeater is further operable to receive from one or more of a base station or other node information specifying the first amount and the second amount.

25. The frequency translating repeater of claim 21, wherein the repeater is further operable to:

frequency shift a first portion of the spectrum of the first user signal by a third amount to produce a first shifted first user signal;

frequency shift a second portion of the spectrum of the first user signal by a fourth amount to produce a second shifted first user signal; and

form a repeater signal comprising the first and second shifted first user signals.

26. The frequency translating repeater according to claim 21, wherein the spectrum of the repeater signal overlaps with the spectrum of the multi-user signal.

27. The frequency translating repeater according to claim 21, wherein the repeater comprises:

a plurality of filters for filtering the multi-user signal to produce a corresponding plurality of signals; and

a plurality of modulators for modulating each of the corresponding plurality of signals with a complex exponential function of a different frequency.

28. The frequency translating repeater according to claim 21, wherein the repeater comprises a first band pass filter for isolating the first user signal from the multi-user signal and a second band pass filter for isolating the second user signal from the multi-user signal.

29. The frequency translating repeater according to claim 27, wherein a scaling factor is associated with at least one of the filters, said scaling factor specifying a power level for the transmission of the first user signal in the repeater signal, thereby enabling band-specific power control.

30. The frequency translating repeater according to claim 21, wherein the frequency translating repeater is configured to be controlled by a base station.

31. The frequency translating repeater according to claim 30, wherein the frequency translating repeater is configured to receive from the base station a control message setting the first amount and the second amount.