EP0844743A2
Expired / Lapsed
EP
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Spread spectrum receiver for use in communication systems
Assignee: Panasonic Holdings Corp
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Filing: 1997-11-24
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Granted: —
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Expires: 2017-11-24
Abstract
Abstract A spread spectrum receiver for use in a mobile communication system is provided which includes a plurality of spread spectrum demodulators, a diversity combiner, a power level detector, a correlation determining circuit, a signal combination determining circuit, and a demodulator phase control circuit.. The correlation determining circuit determines correlation among input multipath signals transmitted through different transmission paths. The signal combination determining circuit selects the same number as that of the spread spectrum demodulators out of the multipath signals, which minimizes a drop in power level of a diversity combined signal outputted from the diversity combiner according to the determined correlation. The demodulator phase control circuit controls phases of demodulating operations of the spread spectrum demodulators to demodulate the selected multipath signals, respectively.
Inventors
- 👤 Takayuki Nakano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:28
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/7097; H04B1/711; H04W; H04W52/00; H04W52/04; H04W52/38; H04W52/42; H04B1/7115; H04B7/00; H04B7/24; H04B7/26; H04B7/2628; H04B1/7113; H04B1/712
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
158 words
A spread spectrum receiver for use in a communication
system, the receiver comprising: a plurality of spread spectrum demodulators for
demodulating input multipath signals transmitted through
multiple transmission paths in the form of spread spectrum
waves having different phases to provide demodulated signals,
respectively; a diversity combiner for combining the demodulated
signals to produce a diversity combined signal; a power level detector for detecting power levels of
the multipath signals, respectively; correlation determining means for determining
correlation among the multipath signals; selecting means for selecting a number of signals,
equal to that of said spread spectrum demodulators, out of
the multipath signals, which minimize a drop in power level
of the diversity combined signal according to the correlation
determined by said correlation determining means; and a phase determining circuit for determining phases of
demodulating operations of said spread spectrum demodulators
so that the multipath signals selected by said selecting
means undergo demodulation in said spread spectrum
demodulators, respectively.
Claim 2
Dependent Claim
66 words
A receiver according to claim 1, wherein said
correlation determining means is adapted to determine a
cross-correlation value in each of all possible combinations
of any two of the multipath signals, and wherein said
selecting means is adapted to select as many multipath
signals as the number of said spread spectrum demodulators in
the order of showing a smaller cross-correlation value and a
greater power level.
Claim 3
Dependent Claim
43 words
A receiver according to claim 2, wherein said selecting
means is adapted to remove a smaller in power level of one of
said combinations showing the greatest cross-correlation
value to select as many multipath signals as the number of
said spread spectrum demodulators.
Claim 4
Dependent Claim
77 words
A receiver according to claim 3, wherein said selected
means is adapted, if there are left the multipath signals
greater in number than said spread spectrum demodulators
after the smaller in power level of one of said combinations
showing the greatest cross-correlation value is removed, to
remove a smaller in power level of one of said combinations
showing the second greatest cross-correlation value to select
as many multipath signals as the number of said spread
spectrum demodulators.
Claim 5
Dependent Claim
66 words
A receiver according to claim 1, wherein said
correlation determining means is adapted to determine a
co-variance value in each of all possible combinations of any
two of the multipath signals, and wherein said selecting
means is adapted to select as many multipath signals as the
number of said spread spectrum demodulators in the order of
showing a smaller co-variance value and a greater power
level.
Claim 6
Dependent Claim
43 words
A receiver according to claim 5, wherein said selecting
means is adapted to remove a smaller in power level of one of
said combinations showing the greatest co-variance value to
select as many multipath signals as the number of said spread
spectrum demodulators.
Claim 7
Dependent Claim
66 words
A receiver according to claim 1, wherein said
correlation determining means is adapted to determine a
correlation factor in each of all possible combinations of
any two of the multipath signals, and wherein said selecting
means is adapted to select as many multipath signals as the
number of said spread spectrum demodulators in the order of
showing a smaller correlation factor and a greater power
level.
Claim 8
Dependent Claim
43 words
A receiver according to claim 7, wherein said selecting
means is adapted to remove a smaller in power level of one of
said combinations showing the greatest correlation factor to
select as many multipath signals as the number of said spread
spectrum demodulators.
Claim 9
Dependent Claim
111 words
A receiver according to any of the preceding claims,
wherein said selecting means includes a combined level
calculator and a worst signal combination determining
circuit, said combined level calculator determining the sum
of the power levels in each of all possible combinations of
the same number of the multipath signals as that of said
spread spectrum demodulators to provide a total power level,
said worst signal combination determining circuit determining
frequencies of drops in total power level of said
combinations below a given level to select as many multipath
signals as the number of said spread spectrum demodulators in
the order of showing a lower frequency and a greater power
level.
Claim 10
Dependent Claim
39 words
A receiver according to claim 9, wherein said selecting
means is adapted to determine and exclude one of said
combinations showing the highest frequency to select as many
multipath signals as the number of said spread spectrum
demodulators ultimately.
Claim 11
Dependent Claim
109 words
A receiver according to any one of claims 1 to 8,
wherein said selecting means includes a combined level
calculator and a variance calculator, said combined level
calculator determining the sum of the power levels in each of
all possible combinations of the same number of the multipath
signals as that of said spread spectrum demodulators to
provide a total power level, said variance calculator
determining variance values of the total power levels of said
combinations over a given sampling cycle to select as many
multipath signals as the number of said spread spectrum
demodulators in the order of showing a smaller variance value
and a greater power level.
Claim 12
Dependent Claim
40 words
A receiver according to claim 11, wherein said
selecting means is adapted to determine and exclude one of
said combinations showing the greatest variance value to
select as many multipath signals as the number of said spread
spectrum demodulators ultimately.
Claim 13
Dependent Claim
73 words
A receiver according to claim 1, wherein said
correlation determining means is adapted to determine a time
difference between times at which minimum values in each of
all possible combinations of any two of the multipath signals
appear, and wherein said selecting means is adapted to select
as many multipath signals as the number of said spread
spectrum demodulators in the order of showing a greater time
difference and a greater power level.
Claim 14
Dependent Claim
41 words
A receiver according to claim 13, wherein said
selecting means is adapted to determine and exclude one of
said combinations showing a smaller time difference in
sequence to select as many multipath signals as the number of
said spread spectrum demodulators.
References Cited (Backward Citations)
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