Multiplexed address control in a TDM communication system
First Claim
1. A communication system for sending messages from central communication stations to one or more of a plurality of mobile receivers through Earth orbital relay stations using Time Division Multiplexed communication signals, comprising:
- at least one central communication station having transmission means for transmitting a TDM communication signal which comprises a series of N channels, with D data channels, for D<
N, used exclusively for transmission of message data and A address channels, where A=N-D, used for transmission of address information in the form of receiver addresses for receivers designated to receive messages from said station and corresponding ones of said D channels on which said receiver message is transmitted.
2 Assignments
0 Petitions
Accused Products
Abstract
A message communication system employing one or more centralized communication stations transmitting messages through Earth orbit relay satellites to mobile receivers utilizing Time Division Multiplexed (TDM) communication signals having signal time frames divided into a series of transmission channels. A predetermined number of the channels are designated as address channels with the remainder being used for data transfer. Information transmitted on the address channels is used by receivers to determine both the presence of a message and its corresponding data transmission channel. Each system receiver scans, and tracks only the communication signal address channels until a message addressed to that receiver is detected, at which time the selected receiver changes channels to the designated data channel for reception of the message. Thus, demodulation of the entire communication signal is not required and processing time and power is reduced for the typical waiting condition when messages are not being received. While a message is being received only a portion of the communication signal need to be received, demodulated and decoded. The decoded message is then displayed on a display screen or similar device for the recipient.
105 Citations
21 Claims
-
1. A communication system for sending messages from central communication stations to one or more of a plurality of mobile receivers through Earth orbital relay stations using Time Division Multiplexed communication signals, comprising:
at least one central communication station having transmission means for transmitting a TDM communication signal which comprises a series of N channels, with D data channels, for D<
N, used exclusively for transmission of message data and A address channels, where A=N-D, used for transmission of address information in the form of receiver addresses for receivers designated to receive messages from said station and corresponding ones of said D channels on which said receiver message is transmitted.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
10. A method for sending messages from central communication stations to mobile receivers through Earth orbital relay stations, comprising:
-
generating a TDM communication signal which is divided into a series of N transmission channels; providing digital messages to be transmitted on said channels; assigning at least one receiver destination to each message; assigning at least one of D data channels to each of said messages where D<
N;transferring each of said messages on at least one of said D channels; transferring said channel assignment onto one of A address channels where A=N-D; detecting, demodulating and decoding said TDM communication signal by at least one mobile receiver; adjusting said receiver to detect only of said D data channels of said TDM communication signal in response to said address assignments transmitted on said A address channels; and demodulating said one data channel according to said assignment. - View Dependent Claims (11, 12, 13, 14)
-
-
15. A communication system for sending messages from at least one central communication station to one or more of a plurality of mobile receivers through Earth orbital relay stations using Time Division Multiplexed (TDM) communication signals, said system comprising:
at least one central communication station comprising; transmission means for transmitting a TDM communication signal which comprises a series of N channels, with D data channels where D<
N, said D data channels used for transmission of message data, and with A address channels where A=N-D, said A address channels used for transmission of address information in a form of receiver addresses for receivers designated to receive messages from each station and corresponding ones of said D channels on which said receiver message is transmitted;receiver assignment means for detecting which of said plurality of receivers each message is directed to; channel assignment means for assigning at least one channel to each of said messages at a time from said D channels; address control means for transferring a receiver address and an associated channel assignment onto one of said A channels in response to input messages intended for a receiver; message input means connected to said channel assignment means for receiving digital messages and transferring said messages onto said D channels in response to an assignment from said channel assignment means at a rate of one message per channel; and at least one mobile receiver station comprising; receiver means for detecting, demodulating and decoding said TDM communication signal at a rate of about 1/N times a transmission rate of said communication signal, said receiver means being adjusted to receive a selected one of said A address channels when not receiving a message; and channel selection means connected to said receiver means for adjusting said receiver means to demodulate only a designated one of said D message channels of said TDM communication signal according to a channel assignment received for said mobile receiver on said selected one of said A address channels. - View Dependent Claims (16, 17, 18, 19, 20, 21)
Specification