EP0951091A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Wireless communications system having a space-time architecture employing multi-element antennas at both the transmitter and receiver
Assignee: Nokia of America Corp
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Filing: 1999-04-07
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Granted: —
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Expires: 2019-04-07
Abstract
Abstract The bit rate at which a digital wireless communications system communicates data may be significantly increased by using multiple antennas at both the transmitter and receiver and by decomposing the channel into m subchannels that operate in the same frequency band. The system transmits m one dimensional signals and maximizes the minimum signal-to-noise ratio of the receiver detection process.
Inventors
- 👤 Gerard Joseph Foschini
- 👤 Glenn David Golden
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 08:33
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/204; H01Q3/2605; H01Q3/2611; H04L; H04L1/00; H04L1/02; H04L1/06; H04L1/0618
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
252 words
A communications system comprising a transmitter having k antennas, said transmitter responsive to
receipt of an m-dimensional transmit symbol vector from a source,
components of said transmit symbol vector comprising QAM symbols,
said transmit symbol vector being transmitted over m of the k antennas
using a predetermined modulation technique, where
k ≥ m > 1, and CHARACTERIZED BY a receiver having n antennas for receiving signals
from said transmitter as n-dimensional received signal vectors,
where n ≥ m, each of said received signal vectors comprising a
linear combination of symbols from said transmitter and additive noise, wherein said receiver further comprises a detection processor that processes the n-dimensional received signal
vector to form an estimate of the m-dimensional transmit symbol vector,
the detector further comprises a processor that (a) determines a preferred permutation of
integers 1, 2, ... m, which define an order in which said m components
of said transmit symbol vector are estimated, and in which the preferred
permutation is a function of the signal-to-noise ratios
of the m components, and (b) in the order defined by said preferred permutation then
estimates the (i)-th ordered component of the transmit symbol vector by
nulling out from the received signal vector contributions due to transmit
symbol vector components (i+1 ), (i+2),..... (m) which have not yet been
estimated, and canceling out from the received signal vector
contributions due to transmit symbol vector components (1), (2),... (i-1 )
which have already been estimated, where (i) denotes the ith element of
the preferred permutation.
Claim 2
Dependent Claim
45 words
The communications system of claim 1 wherein the detection
processor is arranged to repeatedly process received training signals
characterizing the signal propagation environment to generate a set of m
spatially matched filter vectors, offering the best Signal-to-Noise Ratio
(SNR) for detecting the m transmitted symbols.
Claim 3
Dependent Claim
27 words
The communications system of claim 1 wherein the order for
detecting the m transmitted symbols maximizes the minimum of the m
signal-to-noise ratios of the detection process.
Claim 4
Dependent Claim
27 words
The communications system of claim 1 wherein the selection of
the transmitter antennas is randomly changed prior to the transmission
of a group of transmit vector symbols.
Claim 5
Dependent Claim
44 words
The communications system of claim 1 further comprising a
feedback channel from the receiver to the transmitter and wherein the
selection of the transmitter antennas is optimized based on signal
propagation environment information that the receiver supplies to the
transmitter via the feedback channel.
Claim 6
Dependent Claim
68 words
The communications system of claim 1 further comprising a
feedback channel from the receiver to the transmitter and wherein the
transmitter transmits substreams of a demultiplexed stream of symbols
supplied by a source over respective ones of a predetermined set of
transmit antennas and changes the selection of antennas forming the set
of antennas based on signal propagation environment information
supplied by the receiver via the feedback channel.
Claim 7
Dependent Claim
53 words
The communications system of claim 1 further comprising a
feedback channel from the receiver to the transmitter and wherein the
transmitter transmits a vector symbol over a subset of the k transmitter
antennas, in which the subset is selected based on signal propagation
environment information supplied by the receiver via a feedback
channel.
Claim 8
Dependent Claim
48 words
The communications system of claim 1 wherein the receiver
has an arbitrary number of receive antennas greater than n and wherein
the n antennas that are used to receive signals from said transmitter as
n-dimensional received signal vectors is a subset of the arbitrary number
of receive antennas.
Claim 9
Dependent Claim
71 words
The communications system of claim 1 wherein the rate at
which symbols may be received accurately at the receiver is proportional
to the number of transmit antennas used to transmit the symbols and
logarithmic in the level of transmitted power so that the level of power at
which symbols may be transmitted at the transmitter may be substantially
decreased by increasing the number of transmit antennas by a relatively
small number.
Claim 10
Dependent Claim
53 words
A wireless transmitter comprising a source of a stream of symbols, a plurality of transmitter antennas, and CHARACTERIZED BY a transmitter processor which demultiplexes the symbol stream
into m substreams of symbols and which then transmits each substream
of symbols over a selected one of the transmitter antennas using a
predetermined modulation technique.
Claim 11
Dependent Claim
38 words
The transmitter of claim 10 wherein said plurality of
transmitter antennas is greater than m antennas, where m > 1, and
wherein selection of the m transmitter antennas used to transmit the m
substreams of symbols is arbitrary.
Claim 12
Dependent Claim
24 words
The transmitter of claim 10 wherein the selection of the
transmitter antennas is randomly changed prior to the transmission of a
group of symbols.
Claim 13
Dependent Claim
53 words
The transmitter of claim 10 further comprising a receiver for receiving the transmitted symbols, and a feedback channel from the receiver to the transmitter and
wherein the transmitter processor optimizes the selection of the
transmitter antennas based on signal propagation environment
information that the receiver supplies to the transmitter via the feedback
channel.
Claim 14
Dependent Claim
57 words
The system of claim 10 further comprising a feedback
channel from a receiver of the transmitted symbols to the transmitter and
wherein the transmitter transmits a vector symbol over a subset of the
plurality of transmitter antennas, in which the subset is selected based
on signal propagation environment information received from the
receiver via the feedback channel.
Claim 15
Dependent Claim
175 words
A wireless receiver comprising a plurality of receiver antennas for respectively receiving a
plurality of n signal components forming a received signal vector, where
n > 1, and CHARACTERIZED BY a processor that stores a received signal vector in memory with
other received signal vectors forming a burst of signal vectors, and a detection processor which processes the stored received signal
vector to determine components of a transmitted signal vector
in an order determined as a function of respective signal-to-noise ratios
determined for particular decision statistics so that (a) interference
stemming from transmitted symbol vector components that have been
processed are canceled out of a signal vector that is currently being
processed, (b) interference stemming from transmitted symbol vector
components that have not yet been processed is nulled out of the signal
vector that is currently being processed by projecting the signal vector
orthogonal to a space occupied by the latter interference, and then
processing the projected signal vector in accordance with a
predetermined demodulation technique to identify the components of the
transmitted symbol vector.
Claim 16
Dependent Claim
42 words
The receiver of claim 15 wherein the detection processor
includes repeatedly processing data characterizing the transmission
environment to generate a set of m spatially matched filter vectors
offering the best Signal-to-Noise Ratio (SNR) for detecting the
components of the transmitted symbol vector.
Claim 17
Dependent Claim
28 words
The receiver of claim 15 wherein the order for detecting the
components of the transmitted symbol vector is to maximize the minimum
signal-to-noise ratio of the detection process.
References Cited (Backward Citations)
No citation records indexed.
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