EP0773638A1
Expired / Lapsed
EP
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Method and apparatus to implement antenna diversity for direct sequence spread spectrum receivers
Assignee: AT&T Inc
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Filing: 1996-11-12
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Granted: —
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Expires: 2016-11-12
Abstract
Abstract Diversity for direct sequence spread spectrum wireless communication systems is provided in a receiver having M antennas (T 1 ,T 2 ). Distinct weighting signals (W 1 (t), W 2 (t)) are applied to information signals received at each of the M antennas, with the weighting signals being, for example, distinct changes in either phase or amplitude. Applying weighting signals to each of the information signals received at the M receiver antennas results in constructive addition (18) of derived signal vectors at predetermined intervals, which eliminates deep fading at the receiver.
Inventors
- 👤 Vijitha Weerackody
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 03:05
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/7097; H04B1/711; H04B1/7115; H04B1/712; H04B1/709; H04B1/7093; H04B7/00; H04B7/02; H04B7/04; H04B7/06; H04B7/0613; H04B7/08; H04B7/0837; H04B7/0842; H04B7/0865
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
77 words
A method of operating a direct-sequence spread spectrum communication system for transmitting an information signal from a transmitter to a receiver, said receiver including a plurality of M antennas, said information signal being received at each of said M antennas, the method comprising the steps of: weighting each information signal received at each of said M antennas with a different time varying weighting signal, and combining each differently weighted information signal to generate a combined received signal.
Claim 2
Dependent Claim
32 words
A method in accordance with Claim 1, wherein the step of weighting each information signal comprises applying a distinct phase shift to each information signal received at each of said M antennas.
Claim 3
Dependent Claim
33 words
A method in accordance with Claim 2, wherein said information signal is comprised of a plurality of information data symbols, said distinct phase shift occurring within a duration of said information data symbols.
Claim 4
Dependent Claim
87 words
A method in accordance with Claim 3, wherein said distinct phase shift comprises phase shift θ 1 (t), and phase shift θ 2 (t), with θ 1 (t) being equal to 0 for all time (t), and θ 2 (t) being equal to 0 for the duration of iT < t < (i + ½)T and equal to π for the duration (i + ½)T < t < (i + 1) T, where T is the duration of an information data symbol and i is an integer.
Claim 5
Dependent Claim
41 words
A method in accordance with Claim 4, wherein the method further comprising the step of adjusting said distinct phase shift such that signal vectors S1 and S2 received at antennas T1 and T2 constructively add to each other during predetermined intervals.
Claim 6
Independent Claim
87 words
A method of operating a direct-sequence spread spectrum communication system for transmitting an information signal from a transmitter to a receiver, said receiver including a plurality of M antennas, said information signal being received at each of said M antennas, the method comprising the steps of: weighting each information signal received at each of said M antennas with a different time varying weighting signal, and adjusting said weighting step such that signal vectors derived from said received information signal constructively add to each other during predetermined intervals.
Claim 7
Dependent Claim
32 words
A method in accordance with Claim 6, wherein the step of weighting each information signal comprises applying a distinct phase shift to each information signal received at each of said M antennas.
Claim 8
Dependent Claim
22 words
A method in accordance with Claim 7, wherein said distinct phase shift varies over M distinct phase shifts between O and 2π.
Claim 9
Dependent Claim
32 words
A method in accordance with Claim 6, wherein the step of weighting each information signal comprises applying a distinct amplitude change to each information signal received at each of said M antennas.
Claim 10
Dependent Claim
25 words
A method in accordance with Claim 6, which further includes the steps of combining each differently weighted information signal to generate a combined received signal.
Claim 11
Dependent Claim
33 words
A method in accordance with Claim 6, wherein said weighing step includes the step of setting a rate of said time varying weighing signal as a percentage of a channel coded symbol rate.
Claim 12
Dependent Claim
22 words
A method in accordance with Claim 11, wherein said percentage is in the range of 1-2% of said channel coded symbol rate.
Claim 13
Dependent Claim
75 words
A direct-sequence spread spectrum communication system for transmitting an information signal from a transmitter to a receiver, said receiver including a plurality of M antennas, said information signal being received at each of said M antennas, said communication system comprising: means for weighting each information signal received at each of said M antennas with a different time varying weighting signal, and means for combining each differently weighted information signal to generate a combined received signal.
Claim 14
Dependent Claim
31 words
A communication system in accordance with Claim 13, wherein said weighting means includes means for applying a distinct phase shift to each information signal received at each of said M antennas.
Claim 15
Dependent Claim
88 words
A communication system in accordance with Claim 14, wherein said distinct phase shift comprises phase shift θ 1 (t), and phase shift θ 2 (t), with θ 1 (t) being equal to 0 for all time (t), and θ 2 (t) being equal to 0 for the duration of iT < t < (i + ½)T and equal to π for the duration (i + ½)T < t < (i + 1) T, where T is the duration of an information data symbol and i is an integer.
Claim 16
Dependent Claim
85 words
A direct-sequence spread spectrum communication system for transmitting an information signal from a transmitter to a receiver, said receiver including a plurality of M antennas, said information signal being received at each of said M antennas, said communication system comprising: means for weighting each information signal received at each of said M antennas with a different time varying weighting signal, and means for adjusting said weighting step such that signal vectors derived from said received information signal constructively add to each other during predetermined intervals.
Claim 17
Dependent Claim
31 words
A communication system in accordance with claim 16 wherein said weighting means includes means for applying a distinct phase shift to each information signal received at each of said M antennas.
Claim 18
Dependent Claim
23 words
A communication system in accordance with Claim 17, wherein said distinct phase shift varies over M distinct phase shifts between O and 2π.
Claim 19
Dependent Claim
31 words
A communication system in accordance with Claim 18, wherein said weighting means includes means for applying a distinct amplitude change to each information signal received at each of said M antennas.
Claim 20
Dependent Claim
81 words
A receiver for use in a direct-sequence spread spectrum communication system where an information signal is transmitted from a transmitter to said receiver, said receiver including a plurality of antennas, said information signal being received at each of said plurality of antennas, said receiver comprising, means for weighting each information signal received at each of said plurality of antennas with a different time varying weighting signal, and means for combining each differently weighted information signal to generate a combined received signal.
Claim 21
Dependent Claim
91 words
A receiver for use in a direct-sequence spread spectrum communication system where an information signal is transmitted from a transmitter to said receiver, said receiver including a plurality of antennas, said information signal being received at each of said plurality of antennas, said receiver comprising, means for weighting each information signal received at each of said plurality of antennas with a different time varying weighting signal, and means for adjusting said weighting step such that signal vectors derived from said received information signal constructively add to each other during predetermined intervals.
Claim 22
Dependent Claim
31 words
A receiver in accordance with claim 21 wherein said weighting means includes means for applying a distinct phase shift to each information signal received at each of said plurality of antennas.
Claim 23
Dependent Claim
24 words
A receiver in accordance with claim 22 wherein said distinct phase shift varies over a plurality of distinct phase shifts between O and 2π.
Claim 24
Dependent Claim
31 words
A receiver in accordance with claim 23 wherein said weighting means includes means for applying a distinct amplitude change to each information signal received at each of said plurality of antennas.
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