Apparatus and method for channel estimation without signaling overhead

• US 20070135166A1
• Filed: 12/09/2005
• Published: 06/14/2007
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: van Rensburg, Cornelius, Khan, Farooq, Ding, Yinong
• Granted Patent: US 7,773,961 B2
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel

Abstract

A base station is disclosed for communicating with a subscriber station in a wireless network without requiring training signaling overhead. The base station is capable of combining a pilot signal with a data symbol and transmitting the combined pilot signal and data symbol to the subscriber station. A power level of the pilot signal is below a power level of the data symbol. The base station may be a single-input, single-output (SISO) antenna system or a multiple-input, multiple-output (MIMO) antenna system.

Claims

1. A base station for communicating with a subscriber station in a wireless network, wherein the base station is capable of combining a pilot signal with a data symbol and transmitting the combined pilot signal and data symbol to the subscriber station.

2. The base station as set forth in claim 1, wherein a power level of the pilot signal is below a power level of the data symbol.

3. The base station as set forth in claim 2, wherein the power level of the pilot signal is at least 12 dB below the power level of the data symbol.

4. The base station as set forth in claim 1, wherein the base station is a single-input, single-output (SISO) system.

5. The base station as set forth in claim 4, wherein the base station is an orthogonal frequency division multiple access (OFDMA) base station.

6. The base station as set forth in claim 4, wherein the base station is a code division multiple access (CDMA) base station.

7. The base station as set forth in claim 1, wherein the base station is a multiple-input, multiple-output (MIMO) system.

8. The base station as set forth in claim 7, wherein the base station is an orthogonal frequency division multiple access (OFDMA) base station.

9. The base station as set forth in claim 7, wherein the base station is a code division multiple access (CDMA) base station.

10. The base station as set forth in claim 7, wherein the base station comprises:

an antenna array comprising M antennas for transmitting data to the plurality of subscriber stations; and

a cyclic prefix insertion block for generating pilot signal preambles transmitted from the M antennas, wherein the cyclic prefix insertion block generates a first pilot signal preamble by adding a first cyclic prefix to a first pilot signal sequence and generates a second pilot signal preamble by adding a second cyclic prefix to a second pilot signal sequence, wherein the second pilot signal sequence is a circularly shifted copy of the first pilot signal sequence and wherein the first pilot signal preamble is combined with a first data symbol and the second pilot signal preamble is combined with a second data symbol.

11. The base station as set forth in claim 10, wherein the combined first pilot signal preamble and first data symbol are transmitted from a first one of the M antennas and the combined second pilot signal preamble and second data symbol are transmitted from a second one of the M antennas, and wherein the combined first pilot signal preamble and first data symbol are transmitted simultaneously with the combined second pilot signal preamble and second data symbol.

12. A method for transmitting from a base station of a wireless network to a subscriber station, the method comprising the steps of:

generating a pilot signal;

combining the pilot signal with a data symbol; and

transmitting the combined pilot signal and data symbol to the subscriber station.

13. The method as set forth in claim 12, wherein a power level of the pilot signal is below a power level of the data symbol.

14. The method as set forth in claim 13, wherein the power level of the pilot signal is at least 12 dB below the power level of the data symbol.

15. The method as set forth in claim 12, wherein the base station comprises a multiple-input, multiple-output (MIMO) antenna system.

16. The method as set forth in claim 15, wherein the base station comprises an antenna array comprising M antennas capable of transmitting data to a plurality of subscriber stations, and wherein the steps of generating and combining further comprise the sub-steps of:

generating a first pilot signal preamble by adding a first cyclic prefix to a first pilot signal sequence;

combining the first pilot signal preamble with a first data symbol;

generating a second pilot signal preamble by adding a second cyclic prefix to a second pilot signal sequence, wherein the second pilot signal sequence is a circularly shifted copy of the first pilot signal sequence; and

combining the second pilot signal preamble with a second data symbol.

17. The method as set forth in claim 16, wherein step of transmitting further comprises the sub-steps of:

transmitting the combined first pilot signal preamble and first data symbol from a first one of the M antennas; and

transmitting the combined second pilot signal preamble and second data symbol from a second one of the M antennas simultaneously with the step of transmitting the combined first pilot signal preamble and first data symbol from the first antenna.

18. A subscriber station capable of communicating with a base station of a wireless network, wherein the subscriber station is capable of receiving an incoming signal transmitted by the base station, wherein the incoming signal comprises a data symbol combined with a pilot signal, the subscriber station comprising:

detection circuitry for detecting the pilot signal; and

cancellation circuitry for canceling the detected pilot signal from the incoming signal to thereby recover the data symbol.

19. The subscriber station as set forth in claim 18, wherein a power level of the pilot signal is below a power level of the data symbol and the subscriber station comprises amplification circuitry for adjusting a signal level of the detected pilot signal prior to canceling the detected pilot signal from the incoming signal.

20. The subscriber station as set forth in claim 19, wherein the subscriber station comprises one of:

1) an orthogonal frequency division multiple access (OFDMA) subscriber station; and

     2) a code division multiple access (CDMA) subscriber station.