Time domain multiple access broadcasting, multipoint, and conferencing communication apparatus and method

• US 4,507,781 A
• Filed: 09/16/1983
• Issued: 03/26/1985
• Est. Priority Date: 03/14/1980
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Krug, Robert W., Gobioff, Bruce D., Brennen, John F., Shabe, John, Alvarez, Joseph A. III
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/533,035
• Time in Patent Office: 557 Days
• Field of Search: 370/104, 370/60, 370/61, 370/94, 179/18 D, 179/18 BC, 358/257
• US Class Current: 370/266
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence

Abstract

A method and apparatus are disclosed for conducting broadcast, multipoint, and conference communications in a TDMA network at various data rates while simultaneously conducting point-to-point communications at other data rates, either between local ports or between geographically remote ports during time intervals within a TDMA burst, which are not necessarily predefined. The disclosed apparatus appends a direct destination address to each point-to-point port communication for transmission over a communications link, to directly address the intended destination port. The disclosed invention appends an indirect destination address to each broadcast communication transmitted over the communications link. A broadcast memory is provided at the receiving end of the communications link, for storing correlated direct addresses which are accessed by the indirect destination addresses, to directly address a plurality of intended destination ports. In this manner, both point-to-point and broadcast-type communications can be carried out for a variety of data rates, during time intervals which are not predetermined within the TDMA burst, and with a high degree of connectivity.

Claims

1. An apparatus for selectively carrying out point-to-point or broadcasting connections in a TDMA satellite communications network between remote earth stations, comprising:

a transmit burst buffer having a plurality of data partitions, each corresponding to a particular local transmitting port, with a first port selectively transmitting point-to-point and a second port selectively transmitting in a broadcast mode to destination ports at said second earth stations, and said transmit burst buffer at said first station having an output connected to TDMA burst transmission means;

a transmit space signaling buffer at said first earth station having a first partition storing a direct destination address corresponding to the data to be transmitted point-to-point from said first local port to a first port in said second earth station and a second partition in said transmit space signaling buffer for storing an indirect broadcast address corresponding to the data stored in said second partition in said transmit burst buffer from said second local port for a broadcast connection, said transmit space signaling buffer having an output connected to said TDMA burst transmission means;

burst logic means at said first station having an input connected to said transmit burst buffer and said transmit space signaling buffer for accessing said point-to-point data in said first partition of said transmit burst buffer and appending to it said direct destination address from said first partition in said transmit space signaling buffer and for accessing said broadcast data stored in said second partition of said transmit burst buffer and appending to it said indirect broadcast address stored in said second partition of said transmit space signaling buffer and directing said data and addresses to said TDMA burst transmission means;

a comparison means in said second earth station having an input connected to a TDMA burst receiving means, for comparing the first direct destination address from said first earth station with the destination address of said second earth station and routing said first point-to-point data received from said first earth station to a first partition in a receive burst buffer in said second earth station;

said comparison means comparing said second indirect broadcast address received from said first earth station with a stored broadcast address and routing said second broadcast data received from said first earth station to a second, common location in said receive burst buffer in response to indirectly addressing a broadcast memory in said second earth station having an input connected to said comparison means and an output connected to said receive burst buffer for accessing said common location in said receive burst buffer;

a plurality of ports at said second earth station being switchably connected to said common location in said receive burst buffer for receiving said second data from said first earth station in broadcast mode;

whereby both point-to-point and broadcasting connections can be established.

2. The apparatus of claim 1, which further comprises:

a transmit burst buffer at said second station having data partitions corresponding to each one of said broadcast destination ports in said second station, for selectively transmitting point-to-point to said second port at said first station, having an output connected to second TDMA burst transmission means;

a transmit space signaling buffer at said second earth station having partitions storing direct destination addresses corresponding to the data to be transmitted point-to-point from said each one of said broadcast destination ports to said second port in said first earth station, having an output connected to said second TDMA burst transmission means;

whereby TDMA multipoint communication connections can be made.

3. The apparatus of claim 1, which further comprises:

a transmit burst buffer at said second station having a plurality of data partitions, each corresponding to one of said broadcast destination ports in said second station, each selectively transmitting in a broadcast mode to other ports including said second port at said first earth station, said transmit burst buffer at said second station having an output connected to second TDMA burst transmission means;

a transmit space signaling buffer at said second earth station having a plurality of partitions storing indirect broadcast addresses corresponding to the data stored in said partitions in said transmit burst buffer at said second station for broadcast connections, having an output connected to said second TDMA burst transmission means;

burst logic means at said second station having an input connected to said transmit burst buffer and said transmit space signaling buffer at said second station for accessing said broadcast data stored in said partitions of said transmit burst buffer and appending to them said corresponding indirect broadcast address stored in said partitions of said transmit space signaling buffer at said second location and directing said data and addresses to said second TDMA burst transmission means;

whereby TDMA conference communication connections can be made.

4. The apparatus of claim 3, wherein said ports are voice ports.

5. A TDMA communications broadcasting system having a plurality of input/output ports at a first station for transferring n_i channels of m data units each per TDMA frame from respective, local data users to a TDMA transmit burst communication link, with a first port transmitting a point-to-point message at a rate R_j and a second port transmitting a broadcast message at a rate R_k, and having a plurality of input/output ports at a second station for transferring n_i of said channels of data from a TDMA receive burst communication link to respective local users on a time interleaved basis during periodic TDMA frames, with a third port receiving said point-to-point message at said rate R_j and a plurality of fourth ports receiving said broadcast message at said rate R_k, comprising:

a transmit burst buffer at said first station having a data input connected to a transmit bus common to the data outputs of said first and second ports and a data output connected to said TDMA transmit burst communication link, for storing n_j partitions of data from said first port and n_k partitions of data for said second port in selected ones of a plurality of addressable storage locations arranged into a plurality of rows;

a transmit signaling buffer at said first station having an output connected to said transmit burst link, with a plurality of storage locations for storing n_j direct destination addresses corresponding to ones of said locations in said transmit burst buffer storing first partitions of data from said first port to be transmitted point-to-point and for storing n_k indirect destination addresses corresponding to other ones of said locations in said transmit burst buffer storing second partitions of data from said second port to be transmitted in broadcast mode;

a burst mechanism at said first station having an output connected to an address input to said transmit burst buffer and also connected to an address input to said transmit signaling buffer, for accessing corresponding ones of said locations in said transmit burst buffer and in said transmit signaling buffer, to append each accessed partition of data to a destination address and transmit them in a TDMA burst over said transmit link;

a detector at said second station having an input connected to said TDMA receive burst communication link, for detecting said direct destination addresses and outputting a first control signal and for detecting said indirect destination addresses and outputting a second control signal;

a receive burst buffer in said second station having a row address input gatably connected by said first control signal to said TDMA receive burst communication link, a data input connected to said receive link and a data output connected to a receive bus common to the data inputs of said third and fourth ports, with a plurality of addressable storage locations arranged into rows and m juxtaposed columns, for storing said n_j first partitions of data at ones of said rows accessed by said direct destination addresses;

a scanner at said second station having a periodic cycle of m scans per TDMA frame, there being a frame rate of f frames per second, with a scan count output connected as a column address input to said receive burst buffer;

a switch control memory at said second station having an address input connectd to a scan output of said scanner, a port select output connected to a control input to each of said third and fourth ports and a stored address output connected to a row address input to said receive burst buffer, for storing n_j control words for said third port, each of said n_j control words issuing a port select signal to said third port and issuing a distinct row address to said receive burst buffer when scanned by said scanner, where n_j =R_j /mf;

a broadcast memory at said second station having an address input gatably connected by said second control signal to said TDMA receive burst communication link and an output connected to said row address input to said receive burst buffer, for storing n_k correlated direct addresses which are accessed by said n_k indirect destination addresses;

said broadcast memory outputting said n_k correlated direct addresses to said receive burst buffer row address input for storing said n_k second partitions of data at ones of said rows so accessed;

said switch control memory storing n_k second control words for each of said fourth ports, each of said second control words issuing a port select to a corresponding one of said fourth ports and a row address to said receive burst buffer which is common to all of said fourth ports and which stores one of said n_k second partitions of data, when scanned by said scanner, where n_k =R_k /mf;

whereby both broadcast and point-to-point communications can be carried out at different data rates during time intervals within the TDMA burst which are not predetermined.

6. The apparatus of claim 5, wherein each of said ports further comprises:

means for transferring n_i channels of (q_i +a_i)m data units each per TDMA transmit frame from said respective local data sources to said TDMA transmit burst communication link on a time interleaved basis during periodic TDMA transmit frames, each port operating at a data rate R_i =(q_i +a_i)mf, where q_i is a positive integer of zero, m is a positive integer and a_i is a fraction between zero and one;

whereby data from local data sources having data rates R_i which are not an integral multiple of the scan count rate mf of said scanner, can be transmitted.

7. The apparatus of claim 5, wherein said ports further include:

data activity compression means for deleting the transmission over said link of repetitive data in consecutive TDMA frames;

whereby said broadcasting connections can be made while data activity compression operations take place.

8. A TDMA communications broadcasting system having a plurality of input/output ports at a first station for transferring n_i channels of m data units each per TDMA frame from respective, local data users to a transmit bus, with a first port transmitting a point-to-point message at a rate R_j and a second port transmitting a broadcast message at a rate R_k, and transferring n_i of said channels of data from a receive bus to said respective local users on a time interleaved basis during periodic TDMA frames, with a third port receiving said point-to-point message at said rate R_j and a plurality of fourth ports receiving said broadcast message at said rate R_k, comprising:

an intranodal buffer at said first station having a data input connected to said transmit bus and a data output connected to said receive bus, for storing data units from said first and second ports in selected ones of a plurality of addressable storage locations arranged into rows and two juxtaposed columns;

a scanner at said first station having a periodic cycle of m scans per TDMA frame, there being a frame rate of f frames per second, with a scan count output connected as a column address input to said intranodal buffer, addressing a first one of said columns during even numbered scans and addressing the second one of said columns during odd numbered scans;

a switch control memory at said first station having an address input connected to a scan output of said scanner, a port select output connected to a control input to each of said ports and a stored address output connected to a row address input to said intranodal buffer, for storing n_i control words for said first, second, third and fourth ports;

said first and third ports having the same data rate R_j having n_j pairs of said control words in said switch control memory, each of said pairs having a first control word in the q-th pair issuing a port select signal to said first port and a row address to the p-th row in said intranodal buffer in even scans of said switch control memory and to the p+1 ST row in said intranodal buffer during odd scans and a second control word in said q-th pair issuing a port select signal to said third port and a row address to the p+1 ST row in said intranodal buffer in even scans of said switch control memory and to the p-th row in said intranodal buffer during odd scans to transfer said point-to-point message from said first to said third port at said rate R_j =n_j /mf;

said second and fourth ports having the same data rate R_k having n_k pairs of said control words in said switch control memory, each of said pairs having a first control word in the q-th pair issuing a port select signal to said third port and a row address to the r-th row in said intranodal buffer in even scans of said switch control memory and to the r+1 ST row in said intranodal buffer during odd scans and a second control word in said q-th pair issuing a port select signal to each of said fourth ports and a row address to the r+1 ST row in said intranodal buffer in even scans of said switch control memory and to the r-th row in said intranodal buffer during odd scans, to transfer said broadcast message from said second port to each of said plurality of fourth ports at said rate R_k =n_k /mf.

9. The apparatus of claim 8, wherein each of said ports further comprises:

means for transferring n_i channels of (q_i +a_i)m data units each per TDMA transmit frame from said respective local data sources to said TDMA transmit burst communication link on a time interleaved basis during periodic TDMA transmit frames, each port operating at a data rate R_i =(q_i +a_i)mf, where q_i is a positive integer or zero, m is a positive integer and a_i is a fraction between zero and one;

whereby data from local data sources having data rates R_i which are not an integral multiple of the scan count rate mf of said scanner, can be transmitted.

10. The apparatus of claim 8, which further comprises:

a transmit burst buffer at said first station having a data input connected to said transmit bus and a data output connected to a TDMA transmit burst communication link, for storing partitions of data from said first and second ports in selected ones of a plurality of addressable storage locations arranged into rows and m juxtaposed colunns, with said scan count output from said scanner connected as a column address input and said stored address output of said switch control memory connected as a row address input;

a transmit signaling buffer at said first station having an output connected to said transmit burst link, with a plurality of storage locations for storing direct destination addresses corresponding to ones of said locations in said transmit burst buffer storing first partitions of data from said first port to be transmitted point-to-point and for storing indirect destination addresses corresponding to other ones of said locations in said transmit burst buffer storing second partitions of data from said second port to be transmitted in broadcast mode;

a burst mechanism at said first station having an output connected to an address input to said transmit burst buffer and connected to an address input to said transmit signaling buffer, for accessing corresponding ones of said locations in said transmit burst buffer and in said transmit signaling buffer, to append each accessed partition of data to a destination address and transmit them in a TDMA burst over said transmit link.

11. The apparatus of claim 10, which further comprises:

a plurality of input/output ports at a second station for transferring n_i of said channels of data from a TDMA receive burst communication link to respective local users on a time interleaved basis during periodic TDMA frames, with a fifth port receiving said point-to-point message at said rate R_j and a plurality of sixth ports receiving said broadcast message at said rate R_k ;

a detector at said second station having an input connected to said TDMA receive burst communication link, for detecting said direct destination addresses and outputting a first control signal and for detecting said indirect destination addresses and outputting a second control signal;

a receive burst buffer in said second station having a row address input gatably connected by said first control signal to said TDMA receive burst communication link, a data input connected to said receive link and a data output connected to said receive link and a data output connected to a receive bus common to the data inputs of said fifth and sixth ports, with a plurality of addressable storage locations arranged into rows and m juxtaposed columns, for storing said first partitions of data at ones of said rows accessed by said direct destination addresses;

a scanner at said second station having a periodic cycle of m scans per TDMA frame, there being a frame rate of f frames per second, with a scan count output connected as a column address input to said receive burst buffer;

a switch control memory at said second station having an address input connected to a scan output of said scanner, a port select output connected to a control input to each of said fifth and sixth ports and a stored address output connected to a row address input to said receive burst buffer, for storing n_j control words for said fifth port, each of said n_j control words issuing a port select signal to said fifth port and issuing a distinct row address to said receive burst buffer when scanned by said scanner, where n_j =R_j /mf;

a broadcast memory at said second station having an address input gatably connected by said second control signal to said TDMA receive burst communication link and an output connected to said row address input to said receive burst buffer, for storing correlated direct addresses which are accessed by said indirect destination addresses;

said broadcast memory outputting said correlated direct addresses to said receive burst buffer row address input for storing said second partitions of data at ones of said rows so accessed;

whereby both broadcast and point-to-point communications can be carried out both intranodally and internodally at different data rates during time intervals within the TDMA burst which are not predetermined.

12. A TDMA communications broadcasting system having a plurality of input/output ports at a first station for transferring a plurality of data units per TDMA frame from respective, local data users to a TDMA communication link, with a first port transmitting a point-to-point message and a second port transmitting a broadcast message, and having a plurality of input/output ports at a second station for transferring said data from said TDMA communication link to respective local users on a time interleaved basis during periodic TDMA frames, with a third port receiving said point-to-point message and a plurality of fourth ports receiving said broadcast message, comprising:

a transmit buffer at said first station having a data input connected to a transmit bus common to the data outputs of said first and second ports and a data output connected to said TDMA communication link, for storing first data from said first port and second data from said second port;

a transmit signaling buffer at said first station having an output connected to said TDMA communication link, for storing a direct destination address corresponding to said first data from said first port to be transmitted point-to-point and for storing an indirect destination address corresponding to second data from said second port to be transmitted in broadcast mode;

a transmit mechanism at said first station having an output connected to an input to said transmit buffer and also connected to an input to said transmit signaling buffer, for accessing said transmit buffer and said transmit signaling buffer, to transmit said direct address with said first data and to transmit said indirect address with said second data over said TDMA communication link;

a detector at said second station having an input connected to said TDMA communication link, for detecting said direct destination address and outputting a first control signal and for detecting said indirect destination address and outputting a second control signal;

a receive buffer in said station having an address input gatably connected by said first control signal to said TDMA communication link, a data input connected to said link and a data output connected to a receive bus common to the data inputs of said third and fourth ports, with two addressable storage locations, for storing said first data at a first of said locations accessed by said direct destination address;

said third port having an input connected to said first location in said receive buffer, for receiving said first data in point-to-point communication mode;

a broadcast memory at said second station having an address input gatably connected by said second control signal to said TDMA communication link and an output connected to an address input to said receive buffer, for storing a correlated direct address which is accessed by said indirect destination address;

said broadcast memory outputting said correlated direct address to said receive buffer address input for storing said second data at a second of said locations so accessed;

said plurality of fourth ports each having an input connected to said second location in said receive buffer, for receiving said second data in broadcast communication mode;

whereby both broadcast and point-to-point communications can be carried out over said TDMA communication link.

13. The TDMA communications broadcasting system of claim 12, which further comprises:

a plurality of input/output ports at a third station for transferring said data from said TDMA communication link to respective local users on a time interleaved basis during periodic TDMA frames, with a plurality of fifth ports receiving said broadcast message, comprising;

a second detector at said third station having an input connected to said TDMA communication link, for detecting said indirect destination address and outputting a third control signal;

a second receive buffer in said third station having an address input, a data input connected to said link and a data output connected to a second receive bus common to the data inputs of said fifth ports, with two addressable storage locations;

a second broadcast memory at said third station having an address input gatably connected by said second control signal to said TDMA communication link and an output connected to said address input to said second receive buffer, for storing a correlated direct address which is accessed by said indirect destination address;

said broadcast memory outputting said correlated direct address to said second receive buffer address input for storing said second data at one of said locations so accessed;

said plurality of fifth ports each having an input connected to said one location so accessed in said second receive buffer, for receiving said second data in broadcast communication mode;

whereby both broadcast and point-to-point communications can be carried out over said TDMA communication link.