Multiple access simplex mode communication systems and methods therefor

• US 5,982,742 A
• Filed: 12/05/1997
• Issued: 11/09/1999
• Est. Priority Date: 12/05/1997
• Status: Expired due to Fees

• Current Assignee: Telecom One Technologies Incorporated (Earthshine International Ltd.)
• Original Assignee: Telecom One Technologies Incorporated (Earthshine International Ltd.)
• Inventors: Tai, Moun-lun, Leung, Kwok-viu, Ng, Ming-lam, Tang, Chi-keung, Leung, Tai-che
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US08/985,857
• Time in Patent Office: 704 Days
• Field of Search: 340/825.04, 340/825.53, 340/825.63, 370/213, 370/201, 370/432, 370/449, 370/326, 370/336, 370/345, 370/205, 359/142, 359/148, 375/200
• US Class Current: 370/213
• CPC Class Codes: H04B 7/2612 Arrangements for wireless medium access control, e.g. by allocating physical layer transmission capacity H04B7/2615 - H04B7/2643 take precedence; provision for broadband connection H04Q11/0478

Abstract

An asynchronous time-hopping multiple access "(ATHMA") protocol and a simplex mode communication system utilizing the same requires no synchronization between transmitting stations, no handshaking between transmitters and receivers and no system manager to coordinate data message transmission. The ATHMA protocol ensures that for an n-channel asynchronous simplex mode communication system, each transmitter repeatedly sends each unique data message n successive times according to its own time-hopping schedule. In the preferred embodiment the time-hopping schedules are coordinated such that at least one duplication of each unique message will not collide with any other messages over a given period. Thus, at most n-1 transmissions out of the total n transmissions of each unique data message will be collided and lost. The ATHMA protocol and communication system of the present invention is ideally suited for applications requiring a low throughput rate and channel capacity. The ATHMA protocol can be applied to various transmissions media such as radio, infrared optics and wired media with little or no modification.

Claims

1. An asynchronous time-hopping multiple access method for use with a simplex mode communications system of the type having at least first and second transmitters which are capable of transmitting messages over a single frequency channel independently of one another, the communication system also having first and second receivers which are capable of independently receiving the messages transmitted by said first and second transmitters and which each have an associated logical channel number, said method comprising the steps of:

inputting into the first and second transmitters, respective first and second data signals to be transmitted by the first and second transmitters;

packing the first and second data signals into a predetermined format having overhead codes including the respective logical channel numbers to thereby form respective first and second data messages to be transmitted by the first and second transmitters;

transmitting the first data message from the first transmitter in accordance with a predetermined first time-hopping schedule which dictates that the first data message be transmitted at least twice;

transmitting the second data message from the second transmitter in accordance with a predetermined second time-hopping schedule which dictates that the second data message be transmitted at least twice, wherein the first and second time-hopping schedules are coordinated to ensure that at least one transmission of each of the first and second data messages does not collide with any other transmissions of the first and second data messages;

receiving the transmitted first and second data messages at the first receiver, said step of receiving at the first receiver including;

determining whether any of the data messages received by the first receiver have collided with any of the other data messages;

determining which of the data messages received by the first receiver include a logical channel number matching the logical channel number associated with the first receiver; and

extracting the data signals from the data messages received by the first receiver which have not collided with any of the other data messages and which include a logical channel number matching the logical channel number associated with the first receiver; and

receiving the transmitted first and second data messages at the second receiver, said step of receiving at the second receiver including;

determining whether any of the data messages received by the second receiver have collided with any of the other data messages;

determining which of the data messages received by the second receiver include a logical channel number matching the logical channel number associated with the second receiver; and

extracting the data signals from the data messages received by the second receiver which have not collided with any of the other received data messages and which include a logical channel number matching the logical channel number associated with the second receiver.

2. The method of claim 1, wherein said step of transmitting the first data message includes,

transmitting the first data message two times within a time period of [2+3p+2p² +p³ ], wherein p is the length of the second data message, wherein the first transmission of the first data message begins at time [0] and wherein the second transmission of the first data message begins at time [1+p];

and

said step of transmitting the second data message includes,

transmitting the second data message two times within a time period of [2+5p+2p² ], wherein p is the length of the first data message, wherein the first transmission of the second data message begins at time [p] and wherein the second transmission of the second data message begins at time [1+3p+p² ].

3. The method of claim 2, wherein said step of transmitting the first data message is repeated after time [2+3p+2p² +p³ ] and wherein said step of transmitting the second data message is repeated after time [2+5p+2p² ].

4. A simplex mode communication system utilizing an asynchronous time-hopping multiple access protocol for transferring data from a plurality of transmitters to at least one receiver, said system comprising:

a first transmitter for transmitting data massages at least in duplicate according to a first time-hopping schedule wherein all of the data messages transmitted by said first transmitter include logical channel data associated with said first transmitter;

a second transmitter for transmitting data messages at least in duplicate according to a second time-hopping schedule, wherein the first and second time-hopping schedules are coordinated to ensure that at least one of each duplicate data message transmitted by said first transmitter does not collide with any data messages transmitted by said second transmitter and that at least one of each duplicate data message transmitted by said second transmitter does not collide with any data messages transmitted by said first transmitter, wherein said first and second transmitters operate independently of one another, and wherein the data messages transmitted by said second transmitter include logical channel data associated with the second transmitter;

a first receiver for receiving data messages transmitted by at least one of said first and second transmitters, said first receiver including logical channel data associated therewith and being responsive to data messages which include logical channel data matching the logical channel data associated with said first receiver, said first receiver discarding collided data messages and being responsive to non-collided data messages such that at least some of the non-collided data messages are utilized by the first receiver in a predetermined manner; and

a second receiver for receiving data transmitted by at least one of said first and second transmitters, said second receiver having logical channel data associated therewith and being responsive to non-collided data messages which include logical channel data matching the logical channel data associated with said second receiver such that the non-collided data messages are utilized by said second receiver in a predetermined manner.

5. An asynchronous time hopping multiple-access communication method for use with a simplex mode communication system of the type having n transmitters which are capable of transmitting messages over a single frequency channel independently of one another, and at least one receiver which is capable of receiving the messages transmitted by the n transmitters, each of the n transmitters having an associated logical channel number, said method comprising the steps of:

inputting into the n transmitters, respective n data signals to be transmitted by the n transmitters;

packing the n data signals into a predetermined format having overhead codes including respective the logical channel numbers to thereby form respective n data messages to be transmitted by the n transmitters;

transmitting the n data messages from the n transmitters in accordance with a predetermined set of n time-hopping schedules which dictate that each of the n transmitters transmits its respective data message n times such that at least one transmission of each of the n data messages does not collide with any other transmissions of the n data messages; and

receiving the transmitted n data messages at the receiver, said step of receiving including;

determining whether any of the data messages received by the first receiver have collided with any of the other transmitted data messages;

determining the logical channel number of at least some of the non-collided data messages received by the receivers; and

utilizing the data signals from the received data messages which have not collided with any of the other data messages and which have logical channel members which match respective channel members of the receivers in a predetermined manner.

6. A simplex mode communication system utilizing an asynchronous time-hopping multiple access protocol for transferring data from a plurality of transmitters to at least one receiver, said system comprising:

a first transmitter for transmitting data massages at least in duplicate according to a first time-hopping schedule wherein all of the data messages transmitted by said first transmitter include logical channel data associated with said first transmitter;

a second transmitter for transmitting data messages at least in duplicate according to a second time-hopping schedule, wherein the first and second time-hopping schedules are coordinated to ensure that at least one of each duplicate data message transmitted by said first transmitter does not collide with any data messages transmitted by said second transmitter and that at least one of each duplicate data message transmitted by said second transmitter does not collide with any data messages transmitted by said first transmitter, wherein said first and second transmitters operate independently of one another, and wherein the data messages transmitted by said second transmitter include logical channel data associated with the second transmitter;

a first receiver for receiving data messages transmitted by at least one of said first and second transmitters, said first receiver comprising;

means for determining whether any of the data messages received by said first receiver have collided with any of the other data messages,

means for determining which of the data messages received by said first receiver include logical channel data matching the logical channel data associated with said first receiver, and

means for outputting the data signals from the data messages received by said first receiver which have not collided with any of the other data messages and which include logical channel data matching the logical channel data associated with said first receiver,

said first receiver discarding collided data messages and being responsive to non-collided data messages such that at least some of the non-collided data messages are utilized by the first receiver in a predetermined manner; and

a second receiver for receiving data transmitted by at least one of said first and second transmitters, wherein said second receiver includes;

means for determining whether any of the data messages received by said second receiver have collided with any of the other data messages,

means for determining which of the data messages received by said second receiver include logical channel data matching the logical channel data associated with said second receiver, and

means for outputting the data signals from the data messages received by said second receiver which have not collided with any of the other received data messages and which include logical channel data matching the logical channel data associated with said second receiver.