Method and apparatus for diversity reception of time-dispersed signals

Claim 2

A receiver for providing diversity reception having correlating means (210,212) for generating a first and second correlation signal from a first and second time-dispersed signal received on a first and second receiver branch (100,101), re-aligning means (214,215) operably coupled to the correlating means (210,212) for generating a first aligned signal by coherently re-aligning the first time-dispersed signal to a reference frequency by using at least the first correlation signal and for generating a second aligned signal by coherently re-aligning the second time-­dispersed signal to the reference frequency by using at least the second correlation signal, and signal generation means (105) operably coupled to re-aligning means (214,215) for generating a signal derived from the first and second aligned signals, the improvement characterized by: the correlating means (210,212) characterized by means for generating the first correlation signal by correlating the first time-dispersed signal received on the first receiver branch (100) against a known reference (104) and means for generating the second correlation signal by correlating the second time-dispersed signal received on the second receiver branch (101) against the known reference (104).

Claim 3

The receiver of claim 1 wherein the known reference (104) is characterized by a known synchronization sequence.

Claim 4

The receiver of claim 1 wherein the signal generation means(­105) is characterized by means for providing bit(by bit selection diversity (300,305).

Claim 5

The receiver of claim 1 wherein the signal generation means (105) is characterized by means for providing maximal ratio combining (420,450).

Claim 6

The receiver of claim 2 wherein the known synchronization sequence is in an assigned time slot of a TDMA signal burst.

Claim 7

The receiver of claim 3 wherein the correlating means (210,212) is further characterized by means for generating s-parameters for both the first receiver branch (100) and the second receiver branch (101) based on an estimated channel impulse response of each receiver branch (100,101), and a matched filter response of each receiver branch.

Claim 8

The receiver as set forth in claim 3 wherein the means (300,305) for providing bit by bit diversity is characterized by: (a) means (300) for selecting between symbol samples in the first aligned signal and symbol samples in the second aligned signal, such that a bit by bit selection results in a symbol array of selected symbol samples; (b) means (300) for determining which aligned signal contributed an appropriate number of the selected symbol samples to the output array; and (c) means (300) for providing a sequence estimator (305) with: (i) the symbol sample array; and (ii) an array of s-parameters associated with the receiver branch whose aligned signal contributed the appropriate number of selected symbol samples.

Claim 9

The receiver in accordance with claim 1 wherein the signal generation means (905) is characterized by: (a) sampling means for sampling signal symbols from each of the aligned signals; (b) symbol summing means, operably coupled with the sampling means, for summing the samples of symbols from each aligned signal thereby forming a combined symbol sample array; (c) parameter summing means, operably coupled to the symbol summing means, for summing s-parameters associated with each receiver branch (100,101) thereby forming a combined 5-parameter array; and (d) means, operably coupled with both summing means, for providing a sequence estimator with: (i) the combined symbol sample array; and (ii) the combined s-parameter array.

Claim 10

The receiver of claim 1 wherein the signal generation means (105) is characterized by means for maximal ratio combining wherein a weighting factor is determined from a Received Signal Strength Indicator (400,405) determined from processed channel sounding techniques using a time-dispersal function, such as a channel impulse response, to determine energy levels of received time-dispersed signals.

Claim 11

The receiver of claim 1 wherein the signal generation means (105) is characterized by means for providing maximal ratio combining by generating a weighting factor based on a measurement of signal strength measured at an intermediate frequency stage.

Claim 12

In a method for providing diversity reception, of the type wherein a first and second correlation signal is generated from a first and second time-dispersed signal received on a first and second receiver branch (100,101), generating a first aligned signal by coherently re-aligning the first correlated signal to a reference frequency by using at least the first correlation signal, generating a second aligned signal by coherently re-aligning the second correlated signal to the reference frequency by using at least the second correlation signal and generating a signal derived from the first and second aligned signals, the improvement characterized by: (a) generating the first correlation signal by correlating the first time-dispersed signal received on the first receiver branch (100) against a known reference (104); and (b) generating the second correlation signal by correlating the second time-dispersed signal received on the second receiver branch (101) against the known reference (104).

Claim 13

In a method for providing diversity reception, of the type wherein a first and second correlation signal is generated from a first and second time-dispersed signal received on a first and second receiver branch (100,101), generating a first aligned signal by coherently re-aligning the first correlated signal to a reference frequency by using at least the first correlation signal, generating a second aligned signal by coherently re-aligning the second correlated signal to the reference frequency by using at least the second correlation signal and generating a signal derived from the first and second aligned signals, the improvement characterized by: (a) generating the first correlation signal by correlating the first time-dispersed signal received on the first receiver branch (100) against a known reference (104); and (b) generating the second correlation signal by correlating the second time-dispersed signal received on the second receiver branch (101) against the known reference (104).

Claim 14

The method of claim 11 wherein the known reference (104) is characterized by an expected known synchronization sequence.

Claim 15

The method of Claim 11 wherein generating a signal derived from the first and second aligned signals is characterized by providing bit by bit selection diversity.

Claim 16

The method of claim 11 wherein generating a signal derived from the first and second aligned signals is characterized by providing maximal ratio combining.

Claim 17

The method of claim 11 wherein the known synchronization sequence is in an assigned time slot of a TDMA signal burst.

Claim 18

The method of claim 11 wherein generating correlation signals is characterized by generating s-parameters for the first receiver branch (100) and the second receiver branch (101) based on an estimated channel impulse response of each receiver branch and a matched filter response for each receiver branch (100,101).

Claim 19

The method of claim 13 wherein providing bit by bit selection diversity is characterized by: (a) selecting between symbol samples in the first aligned signal and symbol samples in the second aligned signal, such that a bit by bit selection results in a symbol array of selected symbol samples; (b) determining which aligned signal contributed an appropriate number of the selected symbol samples to the symbol array; and (c) providing a sequence estimator with: (i) the symbol array; and (ii) an array of 5-parameters associated with the receiver branch whose aligned signal contributed the appropriate number of selected symbol samples.

Claim 20

The method of claim 11 wherein generating the signal derived from the first and second aligned signals is characterized by: (a) sampling signal symbols from each of the aligned signals; (b) summing the samples of symbols from each aligned signal thereby forming a combined symbol sample array; (c) summing the s-parameters associated with each receiver branch (100,101) thereby forming a combined s-parameter array; and (d) providing a sequence estimator with: (i) the combined symbol sample array; and (ii) the combined s-parameter array.

Claim 21

The method of claim 11 wherein generating a signal derived from the first and second aligned signals is characterized by providing maximal ratio combining wherein a weighting factor is determined from a Received Signal Strength Indication determined from processed channel sounding techniques using a time-dispersal function, such as a channel impulse response, to determine energy levels of received time-dispersed signals.

Claim 22

The method of claim 11 wherein generating a signal derived from the first and second aligned signals is characterized by providing maximal ratio combining by generating a weighting factor based on a measurement of signal strength measured at an intermediate frequency stage.

Claim 23

In a method for providing diversity reception, of the type wherein a first and second correlation signal is generated from a first and second digital time-dispersed signal received on a first and second receiver branch (100,101), generating a first aligned signal by coherently re-aligning the first correlated signal to a local oscillator (208) of the first branch by using at least the first correlation signal, generating a second aligned signal by coherently re-aligning the second correlated signal to a local oscillator (209) of the second branch by using at least the second correlation signal and generating a signal derived from the first and second aligned signals, the improvement characterized by: (a) generating the first correlation signal by correlating the first time-dispersed signal received on the first receiver branch against a known synchronization sequence (104); (b) generating the second correlation signal by correlating the second time-dispersed signal received on the second receiver branch against the known synchronization sequence (104); and (c) generating the signal derived from the first and second aligned signals is characterized by: (i) sampling symbols from each of the aligned signals; (ii) selecting appropriate symbol samples from at least one of the aligned signals based on absolute values of at least one symbol from each aligned signal such that a bit by bit selection is made between symbols in the first aligned signal and symbols in the second aligned signal based on the absolute value of each symbol sample thereby forming a symbol array of selected symbol samples; (iii) counting the number of symbol samples selected from each aligned signal; and (iv) providing a sequence estimator with the symbol array and an array of s-parameters associated with the receiver branch (100, 101) having a desired number of counted symbol samples.

Claim 24

In a method for providing diversity reception, of the type wherein a first and second correlation signal is generated from a first and second digital time-dispersed signal received on a first and second receiver branch (100,101), generating a first aligned signal by coherently re-aligning the first correlated signal to a local oscillator (208) of the first branch by using at least the first correlation signal, generating a second aligned signal by coherently re-aligning the second correlated signal to a local oscillator (209) of the second branch by using at least the second correlation signal and generating a signal derived from the first and second aligned signals, the improvement characterized by: (a) generating the first correlation signal by correlating the first time-dispersed signal received on the first receiver branch against a known synchronization sequence (104); (b) generating the second correlation signal by correlating the second time-dispersed signal received on the second receiver branch against the known synchronization sequence (104); and (c) generating the signal derived from the first and second aligned signals is characterized by: (i) sampling symbols from each of the aligned signals; (ii) selecting appropriate symbol samples from at least one of the aligned signals based on absolute values of at least one symbol from each aligned signal such that a bit by bit selection is made between symbols in the first aligned signal and symbols in the second aligned signal based on the absolute value of each symbol sample thereby forming a symbol array of selected symbol samples; (iii) counting the number of symbol samples selected from each aligned signal; and (iv) providing a sequence estimator with the symbol array and an array of s-parameters associated with the receiver branch (100, 101) having a desired number of counted symbol samples.