EP0767546A2
Expired / Lapsed
EP
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Method and apparatus for providing time diversity using multiple base stations
Assignee: AT&T Inc
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Filing: 1996-09-25
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Granted: —
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Expires: 2016-09-25
Abstract
Abstract The invention provides a method and apparatus for transmitting digital signaling information (from 10) to a receiver using a plurality of antennas (55). The invention involves applying a channel code (in 20) to a digital signal producing one or more symbols. A plurality of symbol copies is made and each copy is weighted (in 50) by a distinct time varying function. Each of the antennas which are located at two or more base stations transmits a signal based on one of the weighted symbol copies. Any channel code may be used with the invention, such as a convolutional channel code or block channel code. Weighting provided to symbol copies may involve application of an amplitude gain, phase shift, or both. The present invention may be used in combination with either or both conventional interleavers and constellation mappers.
Inventors
- 👤 Vijitha Weerackody
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 16:30
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/06; H04B7/0613; H04B7/0667; H04B7/0671; H04L; H04L1/00; H04L1/02; H04L1/06
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
106 words
A method of transmitting digital signal information to a receiver with use of a plurality of M antennas, each antenna located at a base station, the method comprising the steps of: applying a channel code to a digital signal to produce one or more symbols; providing a copy of a symbol at each base station; weighting each of the M copies of the symbol with a distinct time varying function to form M weighted symbol copies; substantially simultaneously transmitting M signals with M different antennas, each antenna located at a base station, each transmitted signal based on a distinct one of the M weighted symbol copies.
Claim 2
Dependent Claim
21 words
The method of claim 1 wherein the step of applying a channel code comprises the step of applying a convolutional code.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the step of applying a channel code comprises the step of applying a block code.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein each time varying function provides an amplitude gain to a symbol.
Claim 5
Dependent Claim
13 words
The method of claim 4 wherein the amplitude gain is 1 √ M
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein each time varying function provides a phase shift to a symbol.
Claim 7
Dependent Claim
20 words
The method of claim 6 wherein a phase shift applied to symbols is based upon a transmitted symbol data rate.
Claim 8
Dependent Claim
55 words
The method of claim 6 wherein a phase shift applied to an nth symbol for the mth antenna is 2π f Δ [( m -1)- 1 2 ( M -1)] nT d' wherein f Δ is a fraction of a transmitted symbol data rate and Td is a reciprocal of the transmitted symbol data rate.
Claim 9
Dependent Claim
93 words
The method of claim 6 wherein a phase shill, θ m (l), applied to an nth symbol for the mth antenna is 2 π kM ( m -1)(1- n ), for n ≤1≤( n + M -1), Or 2 π kM ( m -1)(1- M - n+n' +1), for n + M ≤1≤( n + N -1), where k and n' are integers which satisfy the following expressions: (k - 1)M + 1 ≤ N ≤ kM and n'(k - 1)<(l - M - n + 1) ≤ (n' + 1)(k - 1).
Claim 10
Dependent Claim
18 words
The method of claim 1 further comprising the step of processing a plurality of symbols with an interleaver.
Claim 11
Dependent Claim
17 words
The method of claim 1 further comprising the step of processing a symbol with a constellation mapper.
Claim 12
Dependent Claim
14 words
The method of claim 11 wherein the constellation mapper comprises a DPSK constellation mapper.
Claim 13
Dependent Claim
14 words
The method of claim 11 wherein the constellation mapper comprises a PSK constellation mapper.
Claim 14
Dependent Claim
95 words
A transmitter for a wireless communication system for transmitting signals to a receiver, the transmitter comprising: a plurality of base stations, each having a channel coder for receiving a digital information signal and producing one or more symbols based on said digital information signal; an information symbol weighting means at each of said base stations, coupled to each channel coder, each such means for weighting a symbol with a distinct time varying function; and an antenna coupled to a each of said symbol weighting means, for transmitting substantially simultaneously M signals based on weighted symbols.
Claim 15
Dependent Claim
26 words
The transmitter of claim 14 wherein the signals for transmission to a receiver are provided to the transmitter by an information source comprising a telephone network.
Claim 16
Dependent Claim
14 words
The transmitter of claim 14 wherein the channel coder comprises a convolutional channel coder.
Claim 17
Dependent Claim
15 words
The transmitter of claim 14 wherein the channel coder comprises a block code channel coder.
Claim 18
Dependent Claim
25 words
The transmitter of claim 14 wherein one or more of the M information symbol weighting means comprise a multiplier applying the distinct time varying function.
Claim 19
Dependent Claim
17 words
The transmitter of claim 14 wherein the time varying function provides a phase shift to a symbol.
Claim 20
Dependent Claim
18 words
The transmitter of claim 14 wherein the distinct time varying function provides an amplitude gain to a symbol.
Claim 21
Dependent Claim
25 words
The transmitter of claim 14 further comprising a constellation mapper, coupled to receive symbols and to provide mapped symbols to the plurality of weighting means.
Claim 22
Dependent Claim
14 words
The transmitter of claim 21 wherein the constellation mapper comprises a PSK constellation mapper.
Claim 23
Dependent Claim
14 words
The transmitter of claim 21 wherein the constellation mapper comprises a DPSK constellation mapper.
Claim 24
Dependent Claim
21 words
The transmitter of claim 14 further comprising an interleaver, coupled to the channel coder, for producing a plurality of interleaved symbols.
References Cited (Backward Citations)
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