Transit diversity wireless communication

• US 7,308,035 B2
• Filed: 07/29/2002
• Issued: 12/11/2007
• Est. Priority Date: 08/13/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Merigeault, Sandrine, Rouquette, Stéphanie Pascale
• Primary Examiner(s): Payne, David C.
• Assistant Examiner(s): Guarino, Rahel
• Application Number:
  US10/486,474
• Publication Number:
  US 20040252779A1
• Time in Patent Office: 1,961 Days
• Field of Search: 375/267, 375/260, 375/295, 375/299
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

A method of transmitting data from a transmitter (13,24) to a remote receiver (14,28) using transmit diversity wireless communication, the transmitter (13,24) comprising three or more transmit antenna elements (1,2,3,4). The data is encoded in symbol blocks (12), the symbols (s1,s2,s3,s4) of a block (12) being permuted within respective sub-sets of symbols between the transmit antenna elements (1,2,3,4) over time with respective replications and complex conjugations and/or negations. At least one of the sub-sets of said transmit antenna elements (1,2,3,4). The signals transmitted over at least one of the transmit antenna elements (1,2,3,4) are modified as a function of channel information at least approximately related to the channel transfer function (h1,h2,h3 and h4) of the transmitted signals, and the sub-sets of symbols and permuted symbols are permuted over time between said sub-sets of transmit antenna elements, so that the received signal is detectable at the receiver (14,28) using an orthogonal detection matrix scheme.

Claims

1. A method of transmitting data from a transmitter to a remote receiver using transmit diversity wireless communication, said transmitter comprising at least three transmit antenna, elements, the method comprising the step of encoding said data in symbol blocks, which includes

modifying signals to be transmitted over at least one of said transmit antenna elements as a function of channel information at least approximately related to the channel transfer function of the transmitted signals (h₁, h₂, h ₃, and h₄), such that the received signal can be detected at the receiver by a detection scheme using an orthogonal detection code matrix, the signals to be transmitted over at least one of said transmit antenna elements are modified so as to satisfy at least approximately the equation

2. A method as claimed in claim 1, wherein said signals transmitted ever said transmit antenna elements are modified in phase as a function of said channel information.

3. A method as claimed in claim 1, wherein said channel information is a function of signals received at said receiver from said transmitter and is transmitted from said receiver to said transmitter.

4. A method as claimed in claim 1, wherein said receiver additionally comprises transmitting means for transmitting signals over channels similar to the transmit channels of said transmitter, and said transmitter additionally comprises receiving means including said transmit antenna elements for receiving signals transmitted from said transmitting means, characterized in that said channel information is calculated at said transmitter as a function of the channel transfer function of signals transmitted from said transmitting means to said receiving means.

5. A method as claimed in claim 1, wherein said symbols (s₁, s₂, s₃, s₄) are permuted over time within said block between the transmit antenna elements a number of times equal to a power of two, which power is greater than or equal to two.

6. A method as claimed in claim 4, wherein said transmitter comprises three or four of said transmit antenna elements and said symbols (s₁, s₂, s₃, s₄) are permuted over time within said block four times between the transmit antenna elements.

7. A method as claimed in claim 1, wherein said sub-sets of symbols and permuted symbols are permuted over time between said sub-sets of transmit antenna elements without conjugation or negation and said signals transmitted over at least one of said transmit antenna elements are modified so as to satisfy at least approximately the equation

8. A method as claimed in claim 1, wherein said transmitter comprises four of said transmit antenna elements and said signals transmitted over said transmit antenna elements are modified so as to satisfy at least approximately the equations

9. A method as claimed in claim 8, wherein values at least approximately related to w₃ and w₄ are calculated at said receiver as a function of received signals and transmitted from said receiver to said transmitter.

10. A method as claimed in claim 8, wherein said receiver additionally comprises transmitting means for transmitting signals over channels similar to the transmit channels of said transmitter, and said transmitter additionally comprises receiving means including said transmit antenna elements for receiving signals transmitted from said transmitting means, wherein values at least approximately related to w₃ and w₄ are calculated at said transmitter as a function of the channel transfer function (h₁, h₂, h₃ , and h₄) of signals transmitted from said transmitting means to said receiving means.

11. A method as claimed in claim 1, wherein said transmitter comprises three of said transmit antenna elements and said signals transmitted over said transmit antenna elements are modified so as to satisfy at least approximately the equations

12. A method as claimed in claim 11, wherein a value at least approximately related to w₃ is calculated at said receiver as a function of received signals and transmitted from said receiver to said transmitter.

13. A method as claimed in claim 11, wherein said receiver additionally comprises transmitting means for transmitting signals over channels similar to the transmit channels of said transmitter, and said transmitter additionally comprises receiving means including said transmit antenna elements for receiving signals transmitted from said transmitting means, characterized in that a value at least approximately related to w₃ is calculated at said transmitter as a function of the channel transfer function (h₁, h₂, h₃, and h₄) of signals transmitted from said transmitting means to said receiving means.

14. A method as claimed in claim 1, wherein a permutation signal indicative of the number of permutations over time of said symbols (s₁, s₂, s₃, s₄) within said block is transmitted from said transmitter to said receiver and said receiver is responsive to said permutation signal in the numbers of permutations it performs in detecting the data transmitted.

16. A system as claimed in claim 14, wherein said receiver comprises means for calculating said channel information as a function of pilot signals received from said transmitter and for transmitting said channel information from said receiver to said transmitter.

17. A system as claimed in claim 14, wherein said receiver additionally comprises transmitting means for transmitting signals over channels similar to the transmit channels of said transmitter, and said transmitter additionally comprises receiving means including said transmit antenna elements for receiving signals transmitted from said transmitting means, wherein said transmit encoding means at said transmitter is responsive to the channel transfer function of pilot signals transmitted from said transmitting means to said receiving means to calculate said channel information.

15. A system for transmitting data by transmit diversity wireless communication, the system comprising a transmitter and a plurality of said remote receivers, wherein

said transmitter comprising at least three transmit antenna elements and transmit encoding means for encoding data in symbol blocks, said transmit encoding means being arranged for modifying signals transmitted over at least one of said transmit antenna elements as a function of channel information at least approximately related to the channel transfer function (h₁, h₂, h₃, and h₄) of the transmitted signals, such that the received signal can be detected at the receiver by a detection scheme using an orthogonal detection code matrix, said transmit encoding means being arranged to modify the signals transmitted over at least one of said transmit antenna elements so as to satisfy at least approximately the equation

18. A system as claimed in claim 15, wherein said encoding means is arranged to transmit a permutation signal indicative of the number of permutations over time of said symbols within said block and said receiver comprises detection means responsive to said permutation signal in the number of permutations it performs in detecting the data transmitted.

19. A transmitter for transmitting data to a remote receiver by transmit diversity wireless communication, comprising at least three transmit antenna elements and transmit encoding means for encoding data in symbol blocks, said transmit encoding means being arranged for modifying signals transmitted over at least one of said transmit antenna elements as a function of channel information at least approximately related to the channel transfer function (h₁, h₂, h₃, and h₄) of the transmitted signals, such that a received signal can be detected at a receiver by a detection scheme using an orthogonal detection code matrix, said transmit encoding means being arranged to modify the signals transmitted over at least one of said transmit antenna elements so as to satisfy at least approximately the equation

20. A transmitter as claimed in claim 19, for transmitting data to a receiver additionally comprising transmitting means for transmitting signals over channels similar to the transmit channels of said transmitter, wherein said transmitter additionally comprises receiving means including said transmit antenna elements for receiving signals transmitted from said transmitting means, said transmit encoding means at said transmitter being responsive to the channel transfer function (h₁, h₂, h₃, and h₄) of signals transmitted from said transmitting means to said receiving means to calculate said channel information.

21. A transmitter as claimed in claim 19, wherein said encoding means is arranged to transmit a permutation signal indicative of the number of permutations over time of said symbols within said block.

22. A receiver for receiving data transmitted by transmit diversity wireless communication from a transmitter comprising at least three transmit antenna elements, said receiver comprises detection means for detecting data encoded in symbol blocks, from signals transmitted over at least one of said transmit antenna elements having been modified as a function of channel information at least approximately related to the channel transfer function (h₁, h₂, h₃, and h₄) of the transmitted signals such that a received signal can be detected at the receiver by a detection scheme using an orthogonal detection code matrix, said signals transmitted over at least one of said transmit antenna elements having been modified so as to satisfy at least approximately the equation

23. A receiver as claimed in claim 22, wherein said detection means at said receiver comprises means for calculating said channel information as a function of signals received from said transmitter and for transmitting said channel information from said receiver to said transmitter.

24. A receiver as claimed in claim 22, wherein said detection means is responsive to a permutation signal indicative of the number of permutations over time of said symbols within said block, and which is transmitted from said transmitter to said receiver, in the numbers of permutations it performs in detecting the data transmitted.