Methods and apparatus of enhancing performance in wireless communication systems

• US 20050181799A1
• Filed: 04/23/2004
• Published: 08/18/2005
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Srinivasan, Murari
• Granted Patent: US 7,142,864 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/12 Frequency diversity
• 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
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and apparatus for supporting and using multiple communications channels corresponding to different transmit technologies and/or access technologies in parallel within a cell of a wireless communications system are described. Mobile nodes support multiple technologies and can switch between the technology being used at a particular point in time, e.g., from a first channel corresponding to a first technology to a second channel corresponding to a different technology which provides better transmission characteristics, e.g., a better perceived channel quality. Mobiles maintain at least two sets of channel quality information at any one point in time. Mobiles select the better channel and communicate the channel selection to the base station or communicate channel quality information for multiple channels to the basestation and allow the base station to select the channel corresponding to the technology providing the better conditions for the mobile. Different mobiles in the same cell may support different technologies.

Claims

1. A communications method, the method comprising the steps of:

operating a wireless communications terminal to maintain a set of communications quality information for a plurality of different wireless communications channels which can be used to communicate information between a base station and said wireless communications terminal, said plurality of different wireless communications channels including at least a first communications channel and a second communications channel, the first and second communications channels having different quality characteristics which are a function of first and second transmission technologies used to establish said first and second communications channels, respectively, said first and second transmission technologies being different;

operating the wireless terminal to generate a signal as a function of the maintained communications channel quality information corresponding to at least said first and said second communications channels; and

transmitting said signal to said base station.

2. The method of claim 1, wherein said signal provides information on the quality of at least said first and said second communications channel.

3. The method of claim 2, further comprising:

operating the base station to select between multiple ones of said plurality of communications channels to use to communicate information to said wireless communications terminal as a function of the channel quality information included in said signal.

4. The method of claim 1,

wherein said first and second technologies are different incompatible access technologies.

5. The method of claim 4, where the different access technologies include CDMA, OFDM, and narrowband signal carrier technologies.

6. The method of claim 4, where each of the different access technologies corresponds to a different technology standard which defines requirements for complying with the particular access technology, said different access technologies being incompatible as indicated by the technology standard corresponding to one of said different access technologies defining communications requirements which violate the defined requirements of the other different access technologies.

7. The method of claim 1, wherein at least one of the base station and the wireless terminal include multiple antennas, the method further comprising:

making a measurement indicative of a rate of motion of said wireless terminal;

operating one of the base station and wireless terminal to select a communications channel for use in communicating to said wireless terminal as a function of the measurement indicative of the rate of motion of said wireless terminal.

8. The method of claim 7, wherein the step of operating one of the base station and wireless terminal to select a communications channel includes:

selecting the first communications technology when said measurement indicates a first rate of wireless terminal movement, said first communications technology providing a first amount of frequency diversity to the wireless terminal; and

selecting a communications channel corresponding to the second communications technology when said measurement indicates a second rate of wireless terminal movement, the second communications technology using antenna beam forming as a function of feedback information received from the wireless terminal, said second rate of wireless terminal movement being slower than said first rate of wireless terminal movement.

9. The method of claim 7, wherein said step of making a measurement indicative of a rate of motion of said wireless terminal includes making a measurement of a Doppler shift in a signal transmitted between said base station and said wireless terminal.

10. The method of claim 7, wherein said wherein said step of making a measurement indicative of a rate of motion of said wireless terminal includes measuring the rate of change in at least one of:

timing control signals which are used to instruct the wireless terminal to make at clock timing change;

the rate at which the power in a periodically transmitted signal from the wireless terminal changes over with time, a rate of change in a measured quality of a communications channel, and a rate of change in a channel fading measurement.

11. The method of claim 7, wherein the step of operating one of the base station and wireless terminal to select a communications channel includes:

selecting the first communications technology when said measurement indicates a first rate of wireless terminal movement, said first communications technology using a first amount of channel quality feedback signaling from said wireless terminal to said base station; and

selecting a communications channel corresponding to the second communications technology when said measurement indicates a second rate of wireless terminal movement, the second rate of wireless terminal movement being lower than said first rate of wireless terminal movement, the second communications technology using a second amount of channel feedback information, the second amount of channel feedback information being greater than said first amount of channel quality feedback information.

12. The method of claim 11, wherein said first communications technology uses two fixed antennas and is a technology which used an Alamouti transmission method, said first communications technology using zero channel quality feedback signaling to said base station to control the antenna pattern used to transmit signals from said base station.

13. The method of claim 11, wherein. said second transmission method is a beam forming transmission method which involves forming beams as a function of channel quality feedback information received from said wireless terminal.

14. The method of claim 11, wherein both the base station and the wireless terminal include multiple antennas, said second transmission technology is a multiple-input, multiple-output technique.

15. The method of claim 7, wherein the step of operating one of the base station and wireless terminal to select a communications channel includes:

selecting the first communications technology when said measurement indicates a first rate of wireless terminal movement, said first communications technology providing at least one of a higher frequency diversity and a time diversity than a second communications channel; and

selecting the second communications channel corresponding to the second communications technology when said measurement indicates a second rate of wireless terminal movement, the second rate of wireless terminal movement being lower than said first rate of wireless terminal movement, the second communications technology providing a high spatial diversity than is available from the first communications channel corresponding to the first communications technology.

16. The method of claim 7, wherein the step of operating one of the base station and wireless terminal to select a communications channel includes:

selecting a channel in said plurality of channels which provides a higher frequency or time diversity than is available from the non-selected communications channels in said plurality of channels when changes in channel conditions are occurring at a rapid rate; and

selecting another channel in said plurality of channels which provides higher spatial diversity than said channel which is selected when changes in channel conditions are occurring at said rapid rate, said another channel being selected when changes in channel conditions are occurring at a slow rate, said slow rate being a rate which is slower than said rapid rate.

17. The method of claim 1, wherein said plurality of channels are fixed.

18. The method of claim 17, wherein at least some of said plurality of fixed communications channels are periodic in nature with different combinations of channels existing at different points in time, the combination of channels exiting at any point in time being predictable due to the periodic nature of the communications channels.

19. The method of claim 1, wherein the base station periodically reallocates resources between channels corresponding to different technologies based on a predetermined schedule.

20. The method of claim 1, wherein the base station reallocates resources between channels corresponding to different technologies based on signals received from one or more wireless terminals.

21. The method of claim 20, wherein the base station creates a channel corresponding to a particular technology in response to a signal indicating a request for a channel using the particular technology from a wireless terminal.

22. The method of claim 21, wherein the base station maintains said created channel for a period of time which is a function of at least one signal received from said wireless terminal which requested the channel.

23. The method of claim 1, wherein the base station includes multiple antennas, a first set of wireless terminals which interact with said base station including multiple receive antennas, a second set of wireless terminals which interact with said base station including a single antenna, wireless terminals including multiple receive antennas using a communications channel corresponding to a MIMO technology during some points in time with which they interact with said base station and using channels corresponding to technologies which require only a single receive antenna at different points in time when interacting with said base station.

24. The method of claim 23, wherein wireless terminals which include only a single receive antenna interact with said base station using one or more channels corresponding to a technology which does not require multiple receive antennas.

25. The method of claim 1, further comprising:

operating the base station to reallocate communications resources from one of the plurality of communications channels to a communications channel using a different communications technology as a function of the signal received from said wireless terminal.

26. The method of claim 1, further comprising:

operating the wireless terminal to select between the plurality of communications channels based on the maintained set of communications quality information to thereby select the channel corresponding to the transmission technology which provides the better transmission characteristics to said wireless communications terminal; and

wherein said generated signal indicates the channel selection to the base station.

27. The communications method of claim 1, further comprising:

operating the base station to alter the use of communications resources to increase the amount of resources used to generate a communications channel using the technology corresponding to a communications channel selected by the wireless terminal as indicated by information received by the base station.

28. A wireless terminal comprising:

a set of communications quality information for a plurality of different wireless communications channels which can be used to communicate information between a base station and said wireless communications terminal, said plurality of different wireless communications channels including at least a first communications channel and a second communications channel, the first and second communications channels having different quality characteristics which are a function of first and second transmission technologies used to establish said first and second communications channels, respectively, said first and second transmission technologies being different;

means for generating a signal as a function of the maintained communications channel quality information corresponding to at least said first and said second communications channels; and

a transmitter for transmitting said signal to said base station.

29. The wireless terminal of claim 28, wherein said signal provides information on the quality of at least said first and said second communications channel.

30. The wireless terminal of claim 29,

wherein said wireless terminal includes a receiver capable of receiving signals transmitted using said first and second technologies, said first and second technologies being different incompatible access technologies.

31. The wireless terminal of claim 30, where the different access technologies include at least two of CDMA, OFDM, and narrowband signal carrier technologies.

32. The wireless terminal of claim 29, wherein said wireless terminal includes a receiver capable of receiving signals transmitted using said first and second technologies where each of the different access technologies corresponds to a different technology standard which defines requirements for complying with the particular access technology, said different access technologies being incompatible as indicated by the technology standard corresponding to one of said different access technologies defining communications requirements which violate the defined requirements of the other different access technologies.

33. The method of claim 29, wherein said wireless terminal further comprises:

multiple receive antennas,

means for making a measurement indicative of a rate of motion of said wireless terminal; and

means for selecting a communications channel for use in communicating to said wireless terminal as a function of the measurement indicative of the rate of motion of said wireless terminal.

34. A base station comprising:

means for transmitting signals corresponding to a plurality of different communications channels in parallel, at least two of said communications channels corresponding to different access technologies;

means for receiving a signal from a wireless terminal which was generated as a function of signal quality information corresponding to at least two different communications channels, said two different communication channels corresponding to different communications technologies; and

a channel segment allocator for allocating channels segments to said wireless terminal as a function of the received signal.

35. The base station of claim 34, further comprising:

a resource allocation controller for controlling the allocation of resources to communications channels in response to signals received from wireless terminals indicating the selection of a channel corresponding to a particular technology.

36. The base station of claim 35, wherein said resource allocation controller is responsive to channel request information to create a communications channel using a technology selected by a wireless terminal.

37. The base station of claim of claim 35, wherein said resource allocation controller reallocates resources from a communications channel implemented using a first technology to a communications channel using a second technology when the demand for a communications channel using the second technology increases, said first and second communications technologies being different.

38. The base station of claim 34, further comprising:

a channel selection means for selecting a channel to be used to communicate with said wireless terminal as a function of channel information corresponding to at least two different communications channels implemented using different technologies as a function of a signal received from a wireless terminal, the two different communications channels corresponding to different access technologies.