Pilot signal transmission for an orthogonal frequency division wireless communication system

• US 20060209973A1
• Filed: 03/17/2005
• Published: 09/21/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gore, Dhananjay Ashok, Naguib, Ayman Fawzy, Gorokhov, Alexei, Sutivong, Arak, Ji, Tingfang
• Granted Patent: US 9,520,972 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots.

Claims

1. A wireless communication apparatus, comprising:

at least one antenna;

a memory that stores at least one time selective pilot pattern corresponding to a plurality of pilot symbols and at least one frequency selective pilot pattern corresponding to another plurality of pilot symbols; and

a processor coupled with the at least one antenna and the memory, the processor selecting one pilot pattern of the at least one time selective pilot pattern and the at least one frequency selective pilot pattern.

2. The wireless communication apparatus of claim 1, wherein the at least one time selective pilot pattern comprises a plurality of time selective pilot patterns, the at least one frequency selective pilot pattern comprises a plurality of frequency selective pilot patterns, and wherein the processor selects at least one of the plurality of time selective pilot patterns and at least one of the plurality of frequency selective pilot patterns.

3. The wireless communication apparatus of claim 2, wherein the plurality of frequency selective pilot patterns comprise pilot symbol clusters that are orthogonal to each other.

4. The wireless communication apparatus of claim 2, wherein the plurality of time selective pilot patterns comprise pilot symbol clusters that are orthogonal to each other.

5. The wireless communication apparatus of claim 1, wherein the processor selects the at least one of the plurality of time selective pilot patterns and the at least one of the plurality of frequency selective pilot patterns based upon a parameter.

6. The wireless communication apparatus of claim 5, where in the parameter comprises a predetermined threshold.

7. The wireless communication apparatus of claim 5, wherein the parameter is dynamically updated in response to a signal received at the wireless communication apparatus.

8. The wireless communication apparatus of claim 5, wherein the parameter comprises a pre-determined optimization of the network in which the wireless communication apparatus is to operate.

9. The wireless communication apparatus of claim 1, wherein the memory further stores a plurality of sequences that are orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with some of the sequences of the plurality of sequences prior to transmission of the pilot pattern.

10. The wireless communication apparatus of claim 9, wherein the memory further stores another plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with both some of the sequences of the plurality of sequences and some of the another plurality of sequences prior to transmission of the pilot pattern.

11. The wireless communication apparatus of claim 1, wherein the plurality of frequency selective pilot patterns comprise pilot symbol clusters that are quasi-orthogonal to each other.

12. The wireless communication apparatus of claim 1, wherein the plurality of time selective pilot patterns comprise pilot symbol clusters that are quasi-orthogonal to each other.

13. A method of altering pilot symbol transmission in a wireless communication system, comprising:

obtaining information regarding channel conditions from at least a sector of a base station;

determining based upon the information a selectivity of the channel; and

setting a pattern of pilot symbols based upon the selectivity of the channel.

14. The method of claim 13, wherein setting the pattern comprises setting locations of pilot symbol clusters.

15. The method of claim 13, wherein determining the selectivity comprises classifying the channel as frequency selective or time selective.

16. The method of claim 13, wherein determining the selectivity comprises determining the frequency and time selectivity.

17. The method of claim 13, wherein setting comprises setting clusters of pilot symbols to be optimized for both frequency selective and time selective conditions.

18. The method of claim 13, further comprising transmitting information indicating the pattern of pilot symbols to a plurality of users so that the users transmit pilot symbols according to the pattern to the sector of the base station.

19. A wireless communication apparatus capable of transmitting a plurality of symbols each of which is transmitted utilizing a frequency subcarrier of a group of contiguous frequency subcarriers that range from a minimum frequency to a maximum frequency and during a symbol period of a group of contiguous symbol periods that range from a first symbol period to a last symbol period, the wireless communication apparatus comprising:

at least one antenna;

a memory that stores a plurality of pilot patterns each comprising a plurality of clusters each of which comprises a plurality of contiguous pilot symbols, wherein in each cluster only one pilot symbol is assigned the maximum frequency or the minimum frequency as its transmission frequency subcarrier or the first symbol period or the last symbol period as its transmission symbol period; and

a processor coupled with the plurality of antennas and the memory, the processor causing one pilot pattern of the plurality of pilot patterns to be transmitted from the at least one antenna during the group of contiguous symbol periods utilizing the group of contiguous frequency subcarriers.

20. The wireless communication apparatus of claim 19, wherein the plurality of pilot patterns comprise at least one time selective pilot pattern and at least one frequency selective pilot pattern.

21. The wireless communication apparatus of claim 19, wherein the memory further stores a plurality of sequences that are orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with some of the sequences of the plurality of sequences prior to decoding the pilot symbols.

22. The wireless communication apparatus of claim 19, wherein the memory further stores a plurality of sequences that are quasi-orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with some of the sequences of the plurality of sequences prior to decoding the pilot symbols.

23. The wireless communication apparatus of claim 22, wherein the memory further stores another plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with both some of the sequences of the plurality of sequences and some of the another plurality of sequences prior to decoding the pilot symbols.

24. The wireless communication apparatus of claim 19, wherein the processor selects the pilot pattern to be transmitted based upon an instruction received at the at least one antenna.

25. The wireless communication apparatus of claim 19, wherein the at least one antenna comprises a plurality of antennas and wherein the processor causing multiple pilot patterns of the plurality of pilot patterns to be transmitted from the multiple antennas during the group of contiguous symbol periods utilizing the group of contiguous frequency subcarriers.

26. The wireless communication apparatus of claim 25, wherein the memory further stores a plurality of sequences that are orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of each of the multiple pilot pattern with a different sequences of the plurality of sequences prior to transmission of the multiple pilot patterns.

27. The wireless communication apparatus of claim 19, wherein the processor utilizes one pilot pattern of the plurality of pilot patterns to decode multiple pilot symbol groups transmitted by a plurality of wireless devices and received at the at least one antenna.

28. A data packet for transmission in a wireless network, including a preamble portion that identifies a pilot pattern of a plurality of pilot patterns to be transmitted by a receiver of the data packet.

29. The data packet of claim 28, wherein the preamble portion further includes information as to which sequence of a plurality of orthogonal sequence available at a receiver are to be utilized by the receiver of the data packet to multiply the samples that comprise pilot symbols of the pilot pattern prior to transmission of the pilot symbols by the receiver of the data packet.