Frame-interval fault detection in a demand assignment TDMA communication system
First Claim
1. A demand assignment time division multiple access communication system having a central station and a plurality of terminal stations, said central station transmitting a frame sync and a polling signal at periodic intervals to said terminal stations to elicit a response thereform,each of said terminal stations transmitting a test signal in response to reception of said frame sync from the central station, said central station comprising:
- regular-channel receive means and spare-channel receive means for respectively establishing regular and spare channels to said terminal stations for receiving said test signal and an information signal as said elicited response;
fault detection means for detecting the strength of said test signals received by said regular-channel receive means and said spare-channel receive means and determining therefrom whether each of said regular-channel and spare-channel receive means is operating normally or abnormally; and
switch means for exclusively supplying said information signal received by said regular-channel receive means to utilization means when said regular-channel receive means is determined as operating normally, and exclusively supplying said information signal received by said spare-channel receive means to said utilization means when said regular-channel receive means is determined as operating abnormally while said spare-channel receive means is determined as operating normally.
1 Assignment
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Accused Products
Abstract
In a demand assignment TDMA communication system, a central station transmits a frame sync and a polling signal at periodic intervals to terminal stations to elicit a response therefrom. Each terminal station transmits a test signal in response to reception of the frame sync. The central station or a repeater station detects the strength of the test signals received by a regular-channel receiver and a spare-channel receiver and determines if each of the receivers is operating normally or abnormally. The response received by the regular-channel receiver is supplied to a utilization circuit when this receiver is determined as operating normally and the response received by the spare-channel receiver is supplied instead to the utilization circuit when the regular-channel receiver is determined as operating abnormally while the spare-channel receiver is determined as operating normally.
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Citations
8 Claims
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1. A demand assignment time division multiple access communication system having a central station and a plurality of terminal stations, said central station transmitting a frame sync and a polling signal at periodic intervals to said terminal stations to elicit a response thereform,
each of said terminal stations transmitting a test signal in response to reception of said frame sync from the central station, said central station comprising: -
regular-channel receive means and spare-channel receive means for respectively establishing regular and spare channels to said terminal stations for receiving said test signal and an information signal as said elicited response; fault detection means for detecting the strength of said test signals received by said regular-channel receive means and said spare-channel receive means and determining therefrom whether each of said regular-channel and spare-channel receive means is operating normally or abnormally; and switch means for exclusively supplying said information signal received by said regular-channel receive means to utilization means when said regular-channel receive means is determined as operating normally, and exclusively supplying said information signal received by said spare-channel receive means to said utilization means when said regular-channel receive means is determined as operating abnormally while said spare-channel receive means is determined as operating normally. - View Dependent Claims (2, 3)
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4. A demand assignment time division multiple access communication system having a central station and a plurality of terminal stations,
said central station comprising: -
transmit means for generating a frame sync and a polling signal at periodic intervals to sequentially elicit a response from each of said terminal stations and transmitting a time division multiplexed (TDM) signal containing said frame sync, said polling signal and an information signal; regular-channel receive means and spare-channel receive means for receiving signals from each of said terminal stations; switch means having a first position for exclusively connecting the output of said regular-channel receive means to utilization means and a second position for exclusively connecting the output of said spare-channel receive means to said utilization means; and fault detection means for detecting the strength of a test signal at the outputs of both of said regular-channel receive means and said spare-channel receive means and determining therefrom whether said regular-channel receive means is operating normally or abnormally and causing said switch means to switch from said first position to said second position when said regular-channel receive means is determined as operating abnormally while said spare-channel receive means is determined as operating normally, each of said terminal stations comprising; means for receiving said TDM signal from said central station; means for detecting said frame sync containing in said received TDM signal and for transmitting said test signal upon detection of said frame sync; and means for detecting a coincidence between said polling signal contained in said received TDM signal and a station identifier uniquely assigned to each of said terminal stations and transmitting said response upon detection of said coincidence. - View Dependent Claims (5, 6)
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7. A method for switching between a regular-channel receiver and a spare-channel receiver of a master station, said master station establishing a demand assignment time division multiple access communication channel to each of a plurality of remote stations, the method comprising the steps of:
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(a) transmitting a frame sync and a polling signal at periodic intervals from said master station to said remote stations; (b) receiving said frame sync and said polling signal at each of said remote stations; (c) transmitting a test signal to said master station from each of said remote stations upon reception of said frame sync; (d) detecting a coincidence between said received polling signal and a station identifier uniquely assigned to each of said remote stations and transmitting an information signal to said master station upon detection of said coincidence; (e) detecting the strength of said test signals at the outputs of said regular-channel receiver and said spare-channel receiver and determining therefrom whether each of said regular-channel receiver and said spare-channel receiver is operating normally or abnormally; and (f) utilizing exclusively said information signal received by said regular-channel receiver when the same is determined as operating normally and utilizing exclusively said information signal received by said spare-channel receiver when said regular-channel receiver is determined as operating abnormally while said spare-channel receiver is determined as operating normally.
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8. A method for switching between a regular-channel receiver and a spare-channel receiver of a master station, said master station establishing a demand assignment time division multiple access communication channel to each of a plurality of remote stations, the method comprising the steps of:
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(a) generating a frame sync and a polling signal at periodic intervals and transmitting a time division multiplexed (TDM) signal containing said frame sync and polling signal and a first information signal from said master station to said remote stations; (b) receiving said TDM signal at each of said remote stations; (c) detecting said frame sync contained in said received TDM signal and transmitting a test signal upon detection of said frame sync to said master station; (d) detecting a coincidence between said polling signal contained in said received TDM signal and a station identifier uniquely assigned to each of said remote stations and transmitting a second information signal upon detection of said coincidence to said master station; (e) receiving said second information signal and said test signal by said regular-channel receiver and said spare-channel receiver; (f) detecting the strength of said test signals at the outputs of said regular-channel receiver and said spare-channel receiver and determining therefrom whether each of said regular-channel receiver and said spare-channel receiver is operating normally or abnormally; and (g) utilizing exclusively said second information signal received by said regular-channel receiver when said regular-channel receiver is determined as operating normally and utilizing exclusively said second information signal received by said spare-channel receiver when said regular-channel receiver is determined as operating abnormally while said spare-channel receiver is determined as operating normally.
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Specification