MULTIPLE COMPATIBLE OFDM SYSTEMS WITH DIFFERENT BANDWIDTHS

• US 20090116435A1
• Filed: 07/10/2008
• Published: 05/07/2009
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Koorapaty, Havish, Balachandran, Kumar, Ramesh, Rajaram
• Granted Patent: US 8,861,549 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

The technology provides a frame handler, a controller, and a frame structure design for a new radio communications system that provides backward compatibility with an existing or legacy radio communications system with lower signal bandwidth. Data to be transmitted to the new and legacy radio terminals is processed into a frame using a frame format that is compatible with both the new radio access technology system and the legacy radio access technology system so that both types of radio terminals may receive and extract data from the frame intended for each of those radio terminals. The format allows new and legacy radio terminal communications across the different bandwidths employed by the new and legacy systems.

Claims

1. A base station of a radio access network comprising:

transceiver circuitry configured to communicate a frame of information over a radio interface with one or more first radio terminals configured in accordance with a first radio access technology system that permits radio terminal communications over a first channel bandwidth and with one or more second radio terminals configured in accordance with a second radio access technology system that permits radio terminal communications over a second channel bandwidth greater tan the first channel bandwidth; and

a frame handler configured to process data to be transmitted to the first and second radio terminals into a frame using a frame format that is compatible with both the first radio access technology system and the second radio access technology system so that both the first and second radio terminals may receive and extract data from the frame intended for each of those radio terminals.

2. The apparatus in claim 1, wherein the frame format is designed for the second radio access technology system and is backward compatible with the first radio access technology system.

3. The apparatus in claim 2, wherein the first radio access technology system is a system that uses IEEE 802.16e technology and the second radio access technology system is a system that uses IEEE 802.16m technology.

4. The apparatus in claim 3 wherein the second channel bandwidth is a multiple of the first channel bandwidth.

5. The apparatus in claim 1, wherein the frame format includes data transmitted to the one or more first radio terminals using a sub-band of the second channel bandwidth, wherein the sub-band corresponds to the first channel bandwidth.

6. The apparatus in claim 5, wherein the second channel bandwidth includes multiple sub-bands.

7. The apparatus in claim 6, wherein the frame format includes data transmitted to one of the second radio terminals across multiple sub-bands in the frame and data transmitted to each of the one or more first radio terminals using only a single sub-band for each of the first radio terminals.

8. The apparatus in claim 6, wherein the sub-bands are equipped with guard sub-carriers in the first radio access technology, and

wherein the frame format includes data transmitted to the one or more second radio terminals using multiple sub-bands and one or more of the guard sub-carriers.

9. The apparatus in claim 6, wherein one or more system parameters defining the frame format are included in a base sub-band, and

wherein a control message included in the frame is directed to the second radio terminals configured in accordance with the second radio access technology system and indicates system parameters essential to receiving data transmitted to the one or more second radio terminals.

10. The apparatus in claim 6, wherein one or more parameters defining the frame format are included in a base sub-band, and

wherein the base sub-band includes a control message associated with the first radio access technology system that indicates system parameters essential to receiving data transmitted to the one or more second radio terminals.

11. The apparatus in claim 6, wherein one or more parameters defining the frame format are included in a base sub-band, and

wherein a use of one or more preamble sequences indicates which of the sub-bands is the base sub-band.

12. The apparatus in claim 6, wherein a first set of one or more preambles associated with the first radio access technology system included in a sub-band identify that sub-band as being associated with the first radio access technology system and a second, different set of one or more preambles associated with the second radio access technology system included in a sub-band identify that sub-band as being associated with the second radio access technology system.

13. The apparatus in claim 12, wherein one or more parameters defining the frame format are included in a base sub-band with a control message directed to the second radio terminals configured in accordance with the second radio access technology system that indicates system parameters associated with receiving data transmitted to the one or more second radio terminals, and

wherein a subset of the first or second set of one or more preambles indicates which sub-band is the base sub-band.

14. The apparatus in claim 6, wherein bandwidth allocations for a sub-band associated with the first radio access technology system are signaled to radio terminals using one or more control messages within that sub-band such that each of the first radio terminals only receives bandwidth allocations in one sub-band while at least one of the second radio terminals receives bandwidth allocations in multiple sub-bands which are combined and treated as one bandwidth allocation.

15. The apparatus in claim 14, wherein the bandwidth allocations include downlink and uplink bandwidth allocations.

16. A method for operating a base station in a radio access network comprising:

communicating a frame of information over a radio interface with one or more first radio terminals configured in accordance with a first radio access technology system that permits radio terminal communications over a first channel bandwidth and with one or more second radio terminals configured in accordance with a second radio access technology system that permits radio terminal communications over a second channel bandwidth greater than the first channel bandwidth; and

processing data to be transmitted to the first and second radio terminals into a frame using a frame format that is compatible with both the first radio access technology system and the second radio access technology system so that both the first and second radio terminals may receive and extract data from the frame intended for each of those radio terminals.

17. The method in claim 16, wherein the frame format is designed for the second radio access technology system and is backward compatible with the first radio access technology system.

18. The method in claim 17, wherein the first radio access technology system is a system that uses IEEE 802.16e technology and the second radio access technology system is a system that uses IEEE 802.16m technology.

19. The method in claim 18, wherein the first second channel bandwidth is a multiple of the first channel bandwidth.

20. The method in claim 16, wherein the frame format includes data transmitted to the one or more first radio terminals using a sub-band of the second channel bandwidth, wherein the sub-band corresponds to the first channel bandwidth.

21. The method in claim 20, wherein the second channel bandwidth includes multiple sub-bands.

22. The method in claim 21, wherein the frame includes data transmitted to one of the second radio terminals across multiple sub-bands in the frame and data transmitted to each of the one or more first radio terminals using only a single sub-band for each of the first radio terminals.

23. The method in claim 22, wherein control messages indicating the sub-bands used to transmit data to the second radio terminals are transmitted in sub-bands used for transmission of data to the first radio terminals.

24. The method in claim 22, wherein control messages indicating the sub-bands used to transmit data to the second radio terminals are transmitted in sub-bands used for transmission of data only to the second radio terminals.

25. The method in claim 22, wherein the sub-bands are equipped with guard sub-carriers in the first radio access technology, and

wherein the frame includes data transmitted to the one or more second radio terminals using multiple sub-bands and one or more of the guard sub-carriers.

26. The method in claim 22, wherein one or more parameters defining the frame are included in a base sub-band, and

wherein a control message included in the frame is directed to the second radio terminals configured in accordance with the second radio access technology system and indicates system parameters associated with to receiving data transmitted to the one or more second radio terminals.

27. The method in claim 22, wherein one or more parameters defining the frame are included in a base sub-band, and

wherein the base sub-band includes a control message associated with the first radio access technology system that indicates system parameters essential to receiving data transmitted to the one or more second radio terminals.

28. The method in claim 22, wherein one or more parameters defining the frame are included in a base sub-band, and

wherein a use of one or more preambles sequences indicates which of the sub-bands is the base sub-band.

29. The method in claim 22, wherein a first set of one or more preambles associated with the first radio access technology system included in a sub-band identify that sub-band as being associated with the first radio access technology system and a second, different set of one or more preambles associated with the second radio access technology system included in a sub-band identify that sub-band as being associated with the second radio access technology system.

30. The method in claim 29, wherein one or more parameters defining the frame are included in a base sub-band with a control message directed to the second radio terminals configured in accordance with the second radio access technology system that indicates system parameters associated with to receiving data transmitted to the one or more second radio terminals, and

wherein a subset of the first or second set of one or more preambles indicates which sub-band is the base sub-band.

31. The method in claim 22, wherein bandwidth allocations for a sub-band associated with the first radio access technology system are signaled to radio terminals using one or more control messages within that sub-band such that each of the first radio terminals only receives bandwidth allocations in one sub-band while at least one of the second radio terminals receives bandwidth allocations in multiple sub-bands which are combined and treated as one bandwidth allocation.

32. The method in claim 31, wherein the bandwidth allocations include downlink and uplink bandwidth allocations.

33. Radio terminal apparatus, comprising:

transceiver circuitry for communicating a frame of information over a radio interface to a base station, where the radio terminal and the base station are configured in accordance with a first radio access technology system that permits radio communications over a first channel bandwidth that is greater than a second channel bandwidth associated with a second radio access technology that the base station is also configured to support, where the first channel bandwidth configured in accordance with the first radio access technology includes multiple sub-bands, with each sub-band corresponding to the second bandwidth and one or more of the sub-bands is configured in accordance with the second radio access technology; and

a frame handler configured to process data to be transmitted to the base station into a frame using a frame format that is compatible with both the first radio access technology and the second radio access technology, where the data is allocated for transmission across multiple sub-bands.

34. The apparatus in claim 33, wherein the first radio access technology is IEEE 802.16m technology and the second radio access technology uses IEEE 802.16e technology.

35. The apparatus in claim 34, wherein the sub-bands include guard sub-carriers in the second radio access technology, and

wherein the frame format includes data transmitted using multiple sub-bands and one or more of the guard sub-carriers.

36. The apparatus in claim 34, wherein the transceiver circuitry includes an OFDM receiver for demodulating a signal from the base station transmitted across the first channel bandwidth and decode the signal.

37. The apparatus in claim 36, wherein the decoded signal includes a base sub-band containing a control message with one or more parameters defining the frame format.

38. The apparatus in claim 37, wherein a use of one or more preamble sequences sent by the base station indicates which of the sub-bands is the base sub-band.

39. The apparatus in claim 38, wherein the OFDM receiver determines which of the sub-bands is the base sub-band based on the preambles transmitted by the base station within the sub-band.

40. The apparatus in claim 36, wherein the OFDM receiver is configured to process information transmitted in guard sub-carriers of the sub-bands corresponding to the second radio access technology.

41. The apparatus in claim 36, wherein the signal from the base station contains control messages indicating the sub-bands used to transmit data to the second radio terminals is transmitted in sub-bands used for transmission of data to the first radio terminals.

42. The apparatus in claim 36, wherein the signal from the base station contains control messages indicating the sub-bands used to transmit data to the second radio terminals is transmitted in sub-bands used for transmission of data only to the second radio terminals.