Method and apparatus for enhancing communication reception at a wireless communication terminal

• US 6,131,016 A
• Filed: 08/27/1997
• Issued: 10/10/2000
• Est. Priority Date: 08/27/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sollenberger, Nelson Ray, Greenstein, Lawrence Joel
• Primary Examiner(s): Trost, William G.
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US08/920,138
• Time in Patent Office: 1,140 Days
• Field of Search: 455/504, 455/506, 455/522, 455/59, 455/62, 455/69, 455/561, 455/503, 455/70, 455/68, 455/562, 370/203, 370/208, 370/210, 370/330, 370/334, 370/348, 370/525, 370/337, 370/347, 375/299
• US Class Current: 455/69
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

A system provides transmit diversity with feedback to enhance the reception of communication signals at a wireless communication terminal. Multiple antennae are provided at the base station. The multiple antennae transmit multi-carrier information signals such as OFDM including pilot tones. The wireless communication terminal receives the pilot tones and performs processing on those tones to detect the relationship between the information signals transmitted from the various antennae of the base station. A feedback signal, based on the comparison of the pilot tones communicates back to the base station information about the channels of the respective transmit antennae to the terminals. The base station modifies the transmission processing associated with the various transmit antennae based upon the feedback signal. The modified processing improves the reception of the information signals at the wireless communication terminal.

Claims

1. A method for enhancing communication reception at a wireless communication terminal, the method comprising the steps of:

transmitting, from a first antenna, a first multi-carrier signal including N tones, N being an integer greater than 1, the N tones including at least one pilot tone;

transmitting, from a second antenna, a second multi-carrier signal including a plurality of tones the plurality of tones including at least one pilot tone;

receiving a feedback signal from a wireless communication terminal, said feedback signal being representative of a processing of the at least one pilot tone of the first multi-carrier signal and the at least one pilot tone of the second multi-carrier signal;

processing at least one of said first multi-carrier signal and said second multi-carrier signal in response to said feedback signal received from the wireless communication terminal; and

adapting transmission of communication involving the first multi-carrier signal and the second multi-carrier signal in accordance with the received feedback signal.

2. The method of claim 1 wherein said step of processing comprises the substeps of:

selecting said first multi-carrier signal; and

de-selecting said second multi-carrier signal.

3. The method of claim 1 wherein said step of processing comprises the step of adjusting the phase of said second multi-carrier signal with respect to said first multi-carrier signal.

4. The method of claim 1 wherein said step of processing comprises the steps of:

applying a weighting factor to each of said first multi-carrier signal and said second multi-carrier signal wherein said weighting factor includes amplitude and phase adjustment components and

adjusting the weights to maximize a received power for a given transmit power.

5. The method of claim 1, comprising the further steps of transmitting a multi-carrier signal from each of N additional antennae. N being greater than or equal to 1, each multi-carrier signal including a pilot tone;

and

processing each multi-carrier signal in response to said feedback signal

wherein said feedback signal includes representation of a processing of the pilot tones of each multi-carrier signal.

6. A method for enhancing communication reception at a wireless communication terminal, the method comprising the steps of:

transmitting a first signal including N multicarrier tones from a first antenna, N being an integer greater than 1;

transmitting a second signal including at least one pilot tone from a second antenna, said pilot tone corresponding to one of said N multi-carrier tones;

receiving a feedback signal based on an analysis of the first signal and second signal as received at a wireless terminal and;

adapting transmission of communication involving the N multi-carrier tones in accordance with the received feedback signal.

7. The method of claim 6 wherein said second signal includes a plurality of information carrier tones.

8. The method of claim 7 wherein said step of processing comprises the substeps of:

selecting either said first signal or said second signal; and

deselecting the signal not selected in said selecting step.

9. The method of claim 7 wherein said step of processing comprises the step of adjusting the phase of said second signal with respect to said first signal.

10. The method of claim 7 wherein said step of processing comprises the steps of:

applying a weighting factor to each of said first signal and said second signal wherein said weighting factor includes amplitude and phase adjustment components and

adjusting the weights to maximize a received power for a given transmit power.

11. A method for enhancing wireless communication reception at a terminal, the method comprising the steps of:

transmitting a first data frame signal including N multi-carrier tones from a first antenna, N being an integer greater than 1, at least one of which is a pilot tone;

transmitting, in a second frame signal data, a pilot tone from a second antenna, said pilot tone corresponding to one of said N multi-carrier tones wherein said pilot tone falls within a first correlation bandwidth of said N multi-carrier tones;

receiving a feedback signal indicative of reception at the terminal of the transmissions; and

processing a communication to be transmitted to the terminal in accordance with the feedback signal.

12. The method of claim 11 comprising the further steps of:

transmitting a third data frame signal including said multi-carrier tones from said first antenna, including at least one pilot tone falling outside said first correlation bandwidth of said N multi-carrier tones; and

transmitting in a fourth data frame signal from said second antenna, a pilot tone corresponding to one of said N multi-carrier tones falling outside said first correlation bandwidth, wherein said feedback signal is indicative of reception of said pilot tones in said third data frame signal and said fourth data frame signal.

13. The method of claim 12 comprising the further step of estimating at least one of said N multi-carrier tones by interpolating two or more of said N multi-carrier tones using reception information regarding at least two pilot tones.

14. A method for enhancing wireless communication reception at a plurality of terminals, the method comprising the steps of:

providing a multicarrier signal of X tones where X is an integer and X>

2;

creating Y clusters of tones from said X tones where Y is an integer 2≦

Y≦

X each cluster including N carrier tones where N is an integer ≧

1; and

for each cluster of carrier tones,

transmitting from a first antenna a first subset of the cluster'"'"'s carrier tone, one of said tones constituting a first pilot tone;

transmitting from a second antenna a second subset of the cluster'"'"'s carrier tones one such tone constituting a second pilot tone;

receiving a feedback signal from one of the plurality of terminals, said feedback signal being representative of a processing of the first and second pilot tones; and

processing said cluster of carrier tones in response to said feedback signal.

15. A system for providing enhanced communication reception at a wireless communication terminal, the system comprising:

a first transmission antenna;

a second transmission antenna;

a receiver antenna;

a multi-carrier tone generator;

a feedback reception circuit coupled to the receiver antenna; and

a processing circuit coupled to said feedback reception circuit, said multi-carrier tone generator and said first and second transmission antennae such that transmission by the first and second transmission antennae of multi-carrier tones generated by the generator is affected by a feedback signal from a wireless communication terminal received by said feedback reception circuit.

16. A system for improving communication transmission from a base station to a wireless communication terminal, the system comprising:

a complex data source;

a multi-carrier tone generator;

a first transmission antenna;

a first transmission processing path coupling said complex data source, said multicarrier tone generator and said first transmission antenna;

a second transmission antenna;

a second transmission processing path coupling said complex data source said multi-carrier tone generator and said second transmission antenna;

a feedback reception circuit; and

processing control circuitry coupled to said feedback reception circuit, said first transmission processing path and said second transmission processing path, said processing control circuitry affecting the coupling of the complex data source and the multi-carrier tone generator to said first transmission antenna and said second transmission antenna in response to said feedback reception circuit.

17. A system for improving communication transmission from a base station to a wireless communication terminal, the system comprising:

N transmission antennae where N is an integer and N≧

2;

a receiver antenna;

a multi-carrier tone generator;

a feedback reception circuit coupled to the receiver antenna; and

a processing circuit coupled to said feedback reception circuit, said multi-carrier tone generator and said N transmission antennae such that transmission by the N transmission antennae of multi-carrier tones generated by the generator is affected by a feedback signal from a wireless communication terminal received by said feedback reception circuit.