US 2003/0147478 A1 · Complementary code keying demodulation system

Abstract

A complementary code keying (CCK) demodulation system is disclosed, and more particularly relates to both of a bi-stage correlation calculation demodulation system, and a fast walsh block demodulation device at a receiver, wherein the bi-stage correlation calculation demodulation system has a characteristic of bi-stage correlation calculation in which the subsequent second-stage correlation calculations are dependent on the first-stage correlation calculation results by utilizing an incomplete orthogonal property within CCK codewords to arrange the CCK codewords operated in the first-stage correlation calculations and second-stage correlation calculations properly and respectively. Thus, the operation quantities of correlation calculations are reduced substantially, and the codeword transmitted from transmitter is resolved rapidly, so that the complexity of receiver is decreased and the demodulating speed is speeded up. The fast walsh block demodulation device of the present invention comprises: a plurality of adders (operators) constructed to be a first-level correlation calculation circuit and a second-level correlation calculation circuit, and a plurality of process modules constructed to be a third-level correlation calculation circuit, wherein the plurality of process modules having the functions of picking one maximum value from four values and performing third-level correlation calculation of conventional basic fast walsh block demodulation device. Hence, the comparators and the operators used in a conventional basic fast walsh block demodulation device are reduced, so that the goal of speeding up the demodulating speed is achieved, and the cost comes down.

Claims10

Dependent claims

A complementary code keying (CCK) demodulation system utilized in demodulation equipment of WLAN, the CCK demodulation system comprising:

a first-stage calculation apparatus used to perform a plurality of first-stage calculations with an input signal, and to output a plurality of first-stage calculation results, wherein the input signal has a communicative CCK codeword, and thirty-two CCK codewords of sixty-four CCK codewords are utilized in the plurality of first-stage calculations, and the plurality of first-stage calculation results are divided to eight groups, and each of the eight groups consists of at least one first-stage calculation result of the plurality of first-stage calculation results;
a first decision module used to decide and compare the plurality of first-stage calculation results, and if a first-stage calculation result in a group of the eight groups is a maximum value of the plurality of first-stage calculation results and is greater than a maximum threshold, and meanwhile at least one other first-stage calculation result in the group is less than a minimum threshold, the communicative CCK codeword of the input signal is resolved by the first decision module in accordance with the maximum value, and if the maximum value of the plurality of first-stage calculation results is less than the maximum threshold and at least one of the plurality of first-stage calculation results is less than the minimum threshold, the first decision module outputs at least one activated signal;
a second-stage calculation apparatus group used to receive the at least one activated signal and consists of a plurality of second-stage calculation apparatuses that constitute a first sub-apparatus group and a second sub-apparatus group, and according to the at least one activated signal, the first sub-apparatus group or the second sub-apparatus group is activated to perform at least one second-stage calculation with the input signal, and at least one second-stage calculation result is outputted, wherein another thirty-two CCK codewords of sixty-four CCK codewords are utilized in the at least one second-stage calculation;
and
a second decision module used to resolve the communicative CCK codeword of the input signal according to the least one second-stage calculation.

2 more elements

A CCK demodulation system utilized in demodulation equipment of WLAN, the CCK demodulation system comprising:

a first-stage calculation apparatus comprising a first fast walsh block demodulation device and a second fast walsh block demodulation device, wherein the first-stage calculation apparatus is used to perform a plurality of first-stage calculations with an input signal, and to output a plurality of first-stage calculation results of the first fast walsh block demodulation device and a plurality of first-stage calculation results of the second fast walsh block demodulation device, and the input signal has a communicative CCK codeword, and thirty-two CCK codewords of sixty-four CCK codewords are utilized in the plurality of first-stage calculations;
a first decision module used to perform a judgment and comparison step according to the plurality of first-stage calculation results of the first fast walsh block demodulation device and the plurality of first-stage calculation results of the second fast walsh block demodulation device, wherein the judgment and comparison step comprise:
when a maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is greater than a maximum threshold, and a maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is between the maximum threshold and a minimum threshold, regarding a CCK codeword, to which the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device corresponds, as the communicative CCK codeword and using the communicative CCK codeword as an output of the CCK demodulation system;
when the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is greater than the maximum threshold, and the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is between the maximum threshold and the minimum threshold, regarding the CCK codeword, to which the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device corresponds, as the communicative CCK codeword and using the communicative CCK codeword as the output of the CCK demodulation system;
if the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device and the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device are less than the maximum threshold, and meanwhile the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is less than the minimum threshold, outputting a first activated signal;
and
if the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device and the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device are less than the maximum threhold, and meanwhile the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is less than the minimum threshold, outputting a second activated signal;
a second-stage calculation apparatus comprising a third fast walsh block demodulation device and a fourth fast walsh block demodulation device, wherein the second-stage calculation apparatus group is used to receive the first activated signal to activate the third fast walsh block demodulation device or to receive the second activated signal to activate the fourth fast walsh block demodulation device for performing at least one second-stage calculation with the input signal and outputting at least one second-stage calculation result, and other thirty-two CCK codewords of sixty-four CCK codewords are utilized in the at least one second-stage calculations;
and
a second decision module used to resolve the communicative CCK codeword regarded as the output of the CCK demodulation system according to the least one second-stage calculation result.

7 more elements

A CCK demodulation system utilized in demodulation equipment of WLAN, the CCK demodulation system comprising:

a first-stage calculation apparatus comprising a first fast walsh block demodulation device and a second fast walsh block demodulation device, wherein the first-stage calculation apparatus is used to perform a plurality of first-stage calculations with an input signal, and to output a plurality of first-stage calculation results of the first fast walsh block demodulation device and a plurality of first-stage calculation results of the second fast walsh block demodulation device, and the input signal has a communicative CCK codeword, and thirty-two CCK codewords of sixty-four CCK codewords are utilized in the plurality of first-stage calculations, and the first fast walsh block demodulation device is constructed by a plurality of first operators and a plurality of first process modules, and the second fast walsh block demodulation device is constructed by a plurality of second operators and a plurality of second process modules;
a first decision module used to perform a judgment and comparison step according to the plurality of first-stage calculation results of the first fast walsh block demodulation device and the plurality of first-stage calculation results of the second fast walsh block demodulation device, wherein the judgment and comparison step comprise:
when a maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is greater than a maximum threshold, and a maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is between the maximum threshold and a minimum threshold, regarding a CCK codeword, to which the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device corresponds, as the communicative CCK codeword and using the communicative CCK codeword as an output of the CCK demodulation system;
when the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is greater than the maximum threshold, and the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is between the maximum threshold and the minimum threshold, regarding the CCK codeword, to which the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device corresponds, as the communicative CCK codeword and using the communicative CCK codeword as the output of the CCK demodulation system;
if the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device and the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device are less than the maximum threshold, and meanwhile the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device is less than the minimum threshold, outputting a first activated signal;
and
if the maximum value of the plurality of first-stage calculation results of the first fast walsh block demodulation device and the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device are less than the maximum threhold, and meanwhile the maximum value of the plurality of first-stage calculation results of the second fast walsh block demodulation device is less than the minimum threshold, outputting a second activated signal;
a second-stage calculation apparatus comprising a third fast walsh block demodulation device and a fourth fast walsh block demodulation device, wherein the second-stage calculation apparatus group is used to receive the first activated signal to activate the third fast walsh block demodulation device or to receive the second activated signal to activate the fourth fast walsh block demodulation device for performing at least one second-stage calculation with the input signal and outputting at least one second-stage calculation result, and other thirty-two CCK codewords of sixty-four CCK codewords are utilized in the at least one second-stage calculations, and the third fast walsh block demodulation device is constructed by a plurality of third operators and a plurality of third process modules, and the fourth fast walsh block demodulation device is constructed by a plurality of fourth operators and a plurality of fourth process modules;
and
a second decision module used to resolve the communicative CCK codeword regarded as the output of the CCK demodulation system according to the least one second-stage calculation result.

7 more elements

A fast walsh block demodulation structure utilized in a demodulation structure, the fast walsh block demodulation structure comprising:

a plurality of operators used to perform a plurality of first-level calculations and a plurality of second-level calculations with an inputted signal, and to output a plurality of second-level calculation signals, wherein the plurality of second-level calculation signals comprises a plurality of fixed second-level calculation signals and a plurality of unfixed second-level calculation signals;
and
a plurality of process modules, wherein each of the plurality of process modules used to receive two of the plurality of second-level calculation signals comprising a fixed second-level calculation signal of the plurality of fixed second-level calculation signals and a unfixed second-level calculation signal of the plurality of unfixed second-level calculation signals, and each of the plurality of process modules comprises:
a decision module used to decide a first region on which the unfixed second-level calculation signal located and a second region on which the fixed second-level calculation signal located, and to output a first first region code (p1a), a first second region code (p1b), a second first region code (p2a) and a second second region code (p2b);
a first process circuit comprising:
a first rotating angle calculation module used to receive the first first region code (p1a) and the second first region code (p2a), and according to a formula:
Ka=mod4(p2a−p1a) to resolve the Ka, wherein the Ka is a first rotating angle code, and the mod4 is a remainder of dividing four, and then a first rotating angle corresponding to the first rotating angle code is obtained and outputted;
a first rotating process module used to receive the first rotating angle and the unfixed second-level calculation signal and to rotate the unfixed second-level calculation signal according to the first rotating angle for obtaining and outputting a first rotated second-level calculation signal;
and
a first calculator used to receive the first rotated second-level calculation signal and the fixed second-level calculation signal and to perform a first addition with the first rotated second-level calculation signal and the fixed second-level calculation signal for obtaining a first calculation result;
a second process circuit comprising:
a second rotating angle calculation module used to receive the first second region code (p1b) and the second second region code (p2b), and according to a formula:
Kb=mod4(p2b−p1b) to resolve the Kb, wherein the Kb is a second rotating angle code, and then a second rotating angle corresponding to the second rotating angle code is obtained and outputted;
a second rotating process module used to receive the second rotating angle and the unfixed second-level calculation signal and to rotate the unfixed second-level calculation signal according to the first rotating angle for obtaining and outputting a second rotated second-level calculation signal;
and
a second calculator used to receive the second rotated second-level calculation signal and the fixed second-level calculation signal and to perform a second addition with the second rotated second-level calculation signal and the fixed second-level calculation signal for obtaining a second calculation result;
and
a comparator used to receive the first calculation result and the second calculation result, and to perform a comparison with the first calculation result and the second calculation result for obtaining the maximum value regarded as the process module output of each process module of the plurality of process modules.

15 more elements

Dependencies are inferred from the claim text.

Complementary code keying demodulation system

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Complementary code keying demodulation system

Life of this patent

Abstract

Claims10