Method and apparatus for transmission path delay measurements using adaptive demodulation

Claim 3

The method for measuring transmission path delays in a communication system according to claim 1, further comprising the steps of: recording the time of transmission of the delay equalization measurement signal from the control station; and computing a difference between the time of transmission and the corrected time of reception of the delay equalization measurement signal to derive a round trip transmission delay time for the selected remote transmission station.

Claim 4

The method for measuring transmission path delays in a communication system according to claim 2, further comprising the step of computing a difference between the round trip transmission delay time for the selected remote transmission station and an airtime correction factor to obtain a variable path delay time for the selected remote transmission station.

Claim 5

The method for measuring transmission path delays in a communication system according to claim 1, wherein the control station demodulates the received delay equalization measurement signal to recover alternating rising and falling signal edges and includes timing means for generating timing signals, said method further comprising the steps of: detecting signal edges within the demodulated alternating rising and falling signal edges; determining arrival times of detected signal edges; and storing, in a first table, the arrival times of detected signal edges.

Claim 6

The method for measuring transmission path delays in a communication system according to claim 4, wherein said step of analyzing further comprises the steps of: recovering the stored first table; deriving a first time average from the arrival times recovered from the first table; comparing the arrival times recovered from the first table with the first time average derived; and storing in a second table those arrival times of detected signal edges which differ from the derived time average by less than a first predetermined time difference.

Claim 7

The method for measuring transmission path delays in a communication system according to claim 5, wherein said step of analyzing further comprising the steps of: recovering the stored first and second tables; deriving a second time average from the arrival times recovered from the second table; comparing the arrival times recovered from the first table with the second time average derived; and storing in a third table those arrival times of detected signal edges which differ from the second time average derived by less than a second predetermined time difference, the second predetermined time difference being less than the first predetermined time difference.

Claim 8

The method for measuring transmission path delays in a communication system according to claim 6, wherein said step of analyzing further comprising the steps of: recovering the stored first and third tables; deriving a third time average from the arrival times recovered from the third table; comparing the arrival times recovered from the first table with the third time average derived; and storing in a fourth table those arrival times of detected signal edges which differ from the third time average derived by less than a third predetermined time difference, the third predetermined time difference being less than the second predetermined time difference.

Claim 9

The method for measuring transmission path delays in a communication system according to claim 7, wherein said step of analyzing further comprising the steps of: recovering the stored fourth table of arrival times; and deriving a final time average from the arrival times recovered from the fourth table to derive the fine reception time correction factor.

Claim 10

A simulcast transmission system utilizing adaptive demodulation to provide automatic delay equalization measurement, said simulcast transmission system comprising: a remote transmission station capable of retransmitting a received delay equalization measurement signal which includes at least a correction bit pattern signal followed by a synchronization pattern signal; and a control station comprising means for transmitting the delay equalization measurement signal, means for receiving the re-transmitted delay equalization measurement signal, means for correlating the received synchronization pattern signal to obtain a coarse time of reception thereof, means for analyzing the received correction bit pattern signal to derive a fine reception time correction factor, and means for correcting the coarse time of reception with the fine reception time correction factor to obtain a corrected time of reception of the delay equalization measurement signal at the control station.

Claim 11

A simulcast transmission system utilizing adaptive demodulation to provide automatic delay equalization measurement, said simulcast transmission system comprising: a remote transmission station capable of retransmitting a received delay equalization measurement signal which includes at least a correction bit pattern signal followed by a synchronization pattern signal; and a control station comprising means for transmitting the delay equalization measurement signal, means for receiving the re-transmitted delay equalization measurement signal, means for correlating the received synchronization pattern signal to obtain a coarse time of reception thereof, means for analyzing the received correction bit pattern signal to derive a fine reception time correction factor, and means for correcting the coarse time of reception with the fine reception time correction factor to obtain a corrected time of reception of the delay equalization measurement signal at the control station.

Claim 12

The simulcast transmission system according to claim 9, wherein the simulcast transmission system comprises a plurality of remote transmission stations, and wherein said control station further comprises means for selecting at least one of said plurality of remote transmission stations from which the delay equalization measurement signal is to be re-transmitted.

Claim 13

The simulcast transmission system according to claim 10, wherein said control station further comprises: means for recording the time of transmission of the delay equalization measurement signal; and means for computing a difference between the time of transmission and the corrected time of reception of the delay equalization measurement signal to derive a round trip transmission delay time for the selected remote transmission station.

Claim 14

The simulcast transmission system according to claim 11, wherein said control station further comprises means for computing a difference between the round trip transmission delay time for the selected transmission station and an airtime correction factor to obtain a variable path delay time for the selected remote transmission station.

Claim 15

The simulcast transmission system according to claim 9, wherein said control station further comprises: means for demodulating the received delay equalization measurement signal to recover alternating rising and falling signal edges; timing means for generating timing signals; means for detecting signal edges within the demodulated alternating rising and falling signal edges; means for determining arrival times of detected signal edges; and means for storing in a first table, the arrival times of detected signal edges.

Claim 16

The simulcast transmission system according to claim 9, wherein said means for analyzing comprises: means for recovering the stored first table; means for deriving a time average from the recovered arrival times recovered from the first table; means for comparing the arrival times recovered from the first table with the first time average derived; and means for storing in a second table those arrival times of detected signal edges which differ from the derived time average by less than a first predetermined time difference.

Claim 17

The simulcast transmission system according to claim 14, wherein said means for recovering recovers said stored first and second tables, said means for deriving further derives a second time average from the arrival times recovered from the second table, said means for comparing further compares the arrival times recovered from the first table with the second time average derived, and said means for storing stores in a third table those arrival times of detected signal edges which differ from the second time average derived by less than a second predetermined time difference, the second predetermined time difference being less than the first predetermined time difference.

Claim 18

The simulcast transmission system according to claim 15, wherein said means for recovering recovers said stored first and third tables, said means for deriving further derives a third time average from the arrival times recovered from the third table, said means for comparing further compares the arrival times recovered from the first table with the third time average derived, and said means for storing stores in a fourth table those arrival times of detected signal edges which differ from the third time average derived by less than a third predetermined time difference, the third predetermined time difference being less than the second predetermined time difference.

Claim 19

The simulcast transmission system according to claim 16, wherein said means for recovering further recovers the stored fourth table of arrival times, and said means for deriving further derives a final time average from the arrival times recovered from the fourth table to derive the fine reception time correction factor.

Claim 22

The method for measuring transmission path delays in a communication system according to claim 18, wherein the plurality of remote transmission stations demodulates the received delay equalization measurement signal to recover alternating rising and falling signal edges and includes timing means for generating timing signals, said method further comprising the steps of: detecting signal edges within the demodulated alternating rising and falling signal edges; determining arrival times of detected signal edges; and storing, in a first table, the arrival times of detected signal edges.

Claim 23

The method for measuring transmission path delays in a communication system according to claim 18, wherein said step of analyzing further comprises the steps of: recovering the stored first table; deriving a first time average from the arrival times recovered from the first table; comparing the arrival times recovered from the first table with the first time average derived; and storing in a second table those arrival times of detected signal edges which differ from the derived time average by less than a first predetermined time difference.

Claim 24

The method for measuring transmission path delays in a communication system according to claim 20, wherein said step of analyzing further comprising the steps of: recovering the stored first and second tables; deriving a second time average from the arrival times recovered from the second table; comparing the arrival times recovered from the first table with the second time average derived; and storing in a third table those arrival times of detected signal edges which differ from the second time average derived by less than a second predetermined time difference, the second predetermined time difference being less than the first predetermined time difference.

Claim 25

The method for measuring transmission path delays in a communication system according to claim 21, wherein said step of analyzing further comprising the steps of: recovering the stored first and third tables; deriving a third time average from the arrival times recovered from the third table; comparing the arrival times recovered from the first table with the third time average derived; and storing in a fourth table those arrival times of detected signal edges which differ from the third time average derived by less than a third predetermined time difference, the third predetermined time difference being less than the second predetermined time difference.

Claim 26

The method for measuring transmission path delays in a communication system according to claim 22, wherein said step of analyzing further comprising the steps of: recovering the stored fourth table of arrival times; and deriving a final time average from the arrival times recovered from the fourth table to derive the fine reception time correction factor.

Claim 27

A simulcast transmission system utilizing adaptive demodulation to provide automatic delay equalization measurement, said simulcast transmission system comprising: a control station comprising a master clock for generating timing signals, means, responsive to the timing signals for transmitting a delay equalization measurement signal which includes at least a correction bit pattern signal followed by a synchronization pattern signal at predetermined transmission times; and a plurality of remote transmission stations, comprising slave clock for generating timing signals, means, responsive to the timing signals, for receiving the transmitted delay equalization measurement signal, means, responsive to the timing signals, for correlating the received synchronization pattern signal to obtain a coarse time of reception established by the slave clock, means for analyzing the received correction bit pattern signal to derive a fine reception time correction factor, means for adjusting the coarse time of reception established by the slave clocks with the fine reception time correction factor to obtain an adjusted time of reception of the delay equalization measurement signal established by the slave clocks, means for comparing the adjusted time of reception established by the slave clocks with the expected time of arrival to derive arrival time offsets, and means for correcting the delay established at the remote transmission stations by the derived arrival time offsets to adjust for changes in transmission path delays.

Claim 28

A simulcast transmission system utilizing adaptive demodulation to provide automatic delay equalization measurement, said simulcast transmission system comprising: a control station comprising a master clock for generating timing signals, means, responsive to the timing signals for transmitting a delay equalization measurement signal which includes at least a correction bit pattern signal followed by a synchronization pattern signal at predetermined transmission times; and a plurality of remote transmission stations, comprising slave clock for generating timing signals, means, responsive to the timing signals, for receiving the transmitted delay equalization measurement signal, means, responsive to the timing signals, for correlating the received synchronization pattern signal to obtain a coarse time of reception established by the slave clock, means for analyzing the received correction bit pattern signal to derive a fine reception time correction factor, means for adjusting the coarse time of reception established by the slave clocks with the fine reception time correction factor to obtain an adjusted time of reception of the delay equalization measurement signal established by the slave clocks, means for comparing the adjusted time of reception established by the slave clocks with the expected time of arrival to derive arrival time offsets, and means for correcting the delay established at the remote transmission stations by the derived arrival time offsets to adjust for changes in transmission path delays.

Claim 29

The simulcast transmission system according to claim 24, wherein said plurality of remote transmission stations further comprise; means for demodulating the received delay equalization measurement signal to recover alternating rising and falling signal edges; means for detecting signal edges within the demodulated alternating rising and falling signal edges; means for determining arrival times of detected signal edges; and means for storing in a first table, the arrival times of detected signal edges.

Claim 30

The simulcast transmission system according to claim 24, wherein said means for analyzing comprises: means for recovering the stored first table; means for deriving a time average from the recovered arrival times recovered from the first table; means for comparing the arrival times recovered from the first table with the first time average derived; and means for storing in a second table those arrival times of detected signal edges which differ from the derived time average by less than a first predetermined time difference.

Claim 31

The simulcast transmission system according to claim 26, wherein said means for recovering recovers said stored first and second tables, said means for deriving further derives a second time average from the arrival times recovered from the second table, said means for comparing further compares the arrival times recovered from the first table with the second time average derived, and said means for storing further stores in a third table those arrival times of detected signal edges which differ from the second time average derived by less than a second predetermined time difference, the second predetermined time difference being less than the first predetermined time difference.

Claim 32

The simulcast transmission system according to claim 27, wherein said means for recovering recovers said stored first and third tables, said means for deriving further derives a third time average from the arrival times recovered from the third table, said means for comparing further compares the arrival times recovered from the first table with the third time average derived, and said means for storing further stores in a fourth table those arrival times of detected signal edges which differ from the third time average derived by less than a third predetermined time difference, the third predetermined time difference being less than the second predetermined time difference.

Claim 33

The simulcast transmission system according to claim 28, wherein said means for recovering further recovers the stored fourth table of arrival times, and said means for deriving further derives a final time average from the arrival times recovered from the fourth table to derive the fine reception time correction factor.

Claim 34

A communication receiver for use in a communication system which transmits an information signal including at least a first timing portion followed by a second information portion, the information signal being encoded as a plurality of information bits, said communication receiver comprising: means for receiving the transmitted information signal; means for detecting information bit transitions within said timing portion, and for detecting arrival times thereof; means for computing an average bit edge arrival time for the number of arrival times detected; means for computing a sampling point related to the average bit edge arrival time; and means for sampling the information bits received in the first and second information portions at the computed sampling points to detect the information bits contained therein.

Claim 35

A communication receiver for use in a communication system which transmits an information signal including at least a first timing portion followed by a second information portion, the information signal being encoded as a plurality of information bits, said communication receiver comprising: means for receiving the transmitted information signal; means for detecting information bit transitions within said timing portion, and for detecting arrival times thereof; means for computing an average bit edge arrival time for the number of arrival times detected; means for computing a sampling point related to the average bit edge arrival time; and means for sampling the information bits received in the first and second information portions at the computed sampling points to detect the information bits contained therein.

Claim 36

The communication receiver according to claim 30, wherein said first timing portion includes a correction bit pattern signal.

Claim 37

The communication receiver according to claim 30, wherein said first timing portion includes at least a portion of said second information portion.

Claim 38

The communication receiver according to claim 30, wherein said second information portion includes a data packet.

Claim 39

The communication receiver according to claim 30, wherein said second information portion includes a data synchronization pattern.

Claim 40

The communication receiver according to claim 30, wherein said means for computing the average bit edge arrival time computes a rolling average bit edge arrival time as additional information bit transitions are detected.