High capacity reservation multiple access network with multiple shared unidirectional paths

• US 5,963,557 A
• Filed: 04/11/1997
• Issued: 10/05/1999
• Est. Priority Date: 04/11/1997
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures II LLC (Intellectual Ventures LLC)
• Original Assignee: John W. Eng
• Inventors: Eng, John W.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/843,033
• Time in Patent Office: 907 Days
• Field of Search: 370/276, 370/312, 370/352, 370/412, 370/443, 370/445, 370/448, 370/462, 370/468, 370/478, 370/221, 370/432, 370/437, 370/447, 370/458, 455/4.2, 455/5.1
• US Class Current: 370/432
• CPC Class Codes: H04H 20/42 Arrangements for resource management
• CPC Class Codes: H04H 20/76 Wired systems
• CPC Class Codes: H04J 1/12 Arrangements for reducing cross-talk between channels in line transmission systems H04B3/32; in cables or lines H04B3/26 - H04B3/30
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02

Abstract

A method and system are disclosed for enabling point-to-point and multicast communication in a network using three types of communication channels, namely, one or more upstream payload channels, one or more upstream control channels and one or more downstream channels. At least the upstream control and upstream payload channels can carry bitstreams simultaneously; a bitstream may be simultaneously carried on the upstream control and upstream payload channels of a shared medium during overlapping periods of time. Each channel illustratively is divided into slots or mini-slots. Each upstream payload channel is assigned for carrying upstream directed payload bitstreams from stations to a central controller. Each upstream control channel is assigned for carrying upstream directed control bitstreams, such as reservation request bitstreams requesting reservation of time slots of the upstream payload channel, from the stations to the central controller. At least one downstream channel is assigned for carrying at least downstream directed control bitstreams, such as bitstreams containing acknowledgments, collision, status of reservation request, and also containing indications of assigned slots in the upstream payload channel, from the central controller to the stations. The downstream channel may also illustratively carry payload bitstreams.

Claims

1. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller, and

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller and

wherein each of said transmission paths comprises a channel having a unique carrier frequency and bandwidth, and a modulation scheme.

2. The network of claim 1 wherein said network is a two-way hybrid fiber-coax (HFC) cable-TV network, wherein said shared medium comprises fiber-optic and coaxial cables, wherein said centralized controller is a headend controller, and wherein said station is one of a subscriber station, settop box, cable modem, and customer premise equipment.

3. The network of claim 1 wherein said network is a fiber-optic network, and wherein said shared medium is an optical fiber.

4. The network of claim 1 wherein said network comprises three shared unidirectional paths.

5. The network of claim 1 wherein said first path on which payload and control data packets are transmitted is one of plural downstream channels.

6. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein transmissions over said second and third paths are carried out simultaneously during overlapping time periods in said station.

7. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein said network is a wireless network, wherein said shared medium is air, wherein said centralized controller is a base-station, and wherein said station is one of a mobile and stationary communication unit.

8. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein said network is a satellite network, wherein said shared medium is air and space, wherein said centralized controller is a transponder, and wherein said station is one of an earth station and a mobile communication unit.

9. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein each of said second and third transmission paths comprises a channel having a unique set of orthogonal codes and symbols in a S-CDMA modulation scheme.

10. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein each of said transmission paths comprises a channel having a unique set of orthogonal tones and symbols in an OFDM or Multi-Tone modulation scheme.

11. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein said first path is a broadcasting downstream channel carrying MPEG2 transport packets.

12. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein first and second modulation techniques are used for said second path and third path, respectively, wherein said second path being an upstream control channel (UCC) and said third path being an upstream payload channel (UPC), and wherein said first modulation technique enhances robustness and efficiency of said reservation request packet transmission of said UCC without degrading the robustness, efficiency and utilization of said UPC.

13. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein said second path on which reservation request packets are transmitted is one of a plurality of upstream control channels.

14. A network comprising:

a centralized controller,

a station connected to said centralized controller over a shared medium,

a first distinct shared unidirectional transmission path being established between said centralized controller and said station for transmitting data from said centralized controller to said station, wherein the first path being a downstream channel, and

at least a second and third distinct shared unidirectional transmission paths being established between said centralized controller and said station for transmitting data from said station to said centralized controller, wherein the second and third paths each being an upstream channel,

wherein said station transmitting reservation requests data on said second path and receiving a payload data transmission grant from said centralized controller on said first path to transmit payload data on said third path from said station to said centralized controller on time-slots allocated by said centralized controller,

wherein said centralized controller receiving said reservation request data on said second path from said station and transmitting on said first path a payload data transmission grant to said station for transmitting payload data on said third path on said time-slots allocated by said centralized controller, and

wherein said third path on which reservation request packets are transmitted is one of a plurality of upstream payload channels.

15. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein each of said transmission paths comprises a channel having a unique carrier frequency and bandwidth, and a modulation scheme.

16. The method of claim 15 wherein said network is a two-way hybrid fiber-coax (HFC) cable-TV network, wherein said shared medium comprises fiber-optic and coaxial cables, wherein said centralized controller is a headend controller, and wherein said station is one of a subscriber station, settop box, cable modem, and customer premise equipment.

17. The method of claim 15 wherein said network is a fiber-optic network, and wherein said shared medium is an optical fiber.

18. The method of claim 15 wherein said network comprises three shared unidirectional paths.

19. The method of claim 15 wherein said first path on which payload and control data packets are transmitted is one of plural downstream channels.

20. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein transmissions over said second and third paths are carried out simultaneously during overlapping time periods in said particular station.

21. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein said network is a wireless network, wherein said shared medium is air, wherein said centralized controller is a base-station, and wherein said station is one of a mobile and stationary communication unit.

22. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein said network is a satellite network, wherein said shared medium is air and space, wherein said centralized controller is a transponder, and wherein said station is one of an earth station and a mobile communication unit.

23. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein each of said second and third transmission paths comprises a channel having a unique set of orthogonal codes and symbols in a S-CDMA modulation scheme.

24. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein each of said transmission paths comprises a channel having a unique set of orthogonal tones and symbols in an OFDM or Multi-Tone modulation scheme.

25. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein said first path is a broadcasting downstream channel carrying MPEG2 transport packets.

26. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein first and second modulation techniques are used for said second path and third path, respectively, wherein said second path being an upstream control channel (UCC) and said third path being an upstream payload channel (UPC), and wherein said first modulation technique enhances robustness and efficiency of said reservation request packet transmission of said UCC without degrading the robustness, efficiency and utilization of said UPC.

27. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein said second path on which reservation request packets are transmitted is one of a plurality of upstream control channels.

28. A multiple access method via a shared medium of a network, said network comprising a centralized controller and a plurality of stations connected to said centralized controller over a shared medium, wherein a first distinct shared unidirectional transmission path is established between said centralized controller and said stations for broadcasting data from said centralized controller to said stations, at least second and third distinct shared unidirectional transmission paths for transmitting data from said stations to said centralized controller, wherein the first path being a downstream channel and said second and third paths each being an upstream channel, said multiple access method comprising the steps of:

transmitting from a particular station reservation request data on said second path and receiving a payload data transmission grant message from said centralized controller on said first path to transmit payload data packets on said third path from said particular station to said centralized controller on payload time-slots allocated by said centralized controller,

transmitting from said particular station said reservation request data on said second path if said particular station fails to receive a grant message from said centralized controller within a predetermined time delay or if said particular station receives a collision status message from said centralized controller on said first path to retransmit said reservation request according to a collision resolution algorithm,

receiving by said centralized controller said reservation request data on said second path from said particular station, and transmitting on said first path said payload data transmission grant data to said particular station for transmission on said third path of payload data on said payload time-slots allocated by said centralized controller, and

optionally detecting by said centralized controller a collision due to simultaneous transmission of said reservation requests by two or more stations on the same reservation time-slot of said second path, and then transmitting said collision statuses of said reservation requests on said first path to said stations, which will retransmit their reservation requests according to said collision resolution algorithm,

wherein said third path on which reservation request packets are transmitted is one of a plurality of upstream payload channels.

29. A circuit located at a station for interfacing said station to a centralized controller in a network comprising:

a data receiver, and

first and second data transmitters,

wherein said receiver being connected to a first shared unidirectional transmission path between said station and said centralized controller for receiving data transmitted unidirectionally from said centralized controller to said station,

wherein said first transmitter being connected to a second shared unidirectional transmission path between said station and said centralized controller for transmitting reservation request data unidirectionally from said station to said centralized controller,

wherein said second transmitter being connected to a third shared unidirectional transmission path between said station and said centralized controller for transmitting payload data unidirectionally from said station to said centralized controller, and

wherein transmissions over said second and third paths are carried out simultaneously during overlapping time periods in said station.

30. The circuit of claim 29 further comprising a reservation request data transmission circuit corresponding to each said station for transmitting said reservation request data on said second path, and for transmitting payload data on said third path upon receipt of a subsequent payload transmission grant from said centralized controller on said first path.

31. A circuit located at a station for interfacing said station to a centralized controller in a network comprising

a data receiver,

first and second data transmitters, and

wherein said receiver being connected to a first shared unidirectional transmission path between said station and said centralized controller for receiving data transmitted unidirectionally from said centralized controller to said station,

wherein said first transmitter being connected to a second shared unidirectional transmission path between said station and said centralized controller for transmitting reservation request data unidirectionally from said station to said centralized controller,

wherein said second transmitter being connected to a third shared unidirectional transmission path between said station and said centralized controller for transmitting payload data unidirectionally from said station to said centralized controller,

a retransmission decision circuit which includes a collision resolution algorithm for responding to said receiver receiving from said centralized controller on said first path a bitstream containing an indication that a collision has occurred in said second path by causing said first transmitter to re-transmit said reservation request on said second path.

32. A circuit located at a centralized controller for interfacing said centralized controller to a plurality of stations in a network comprising:

a data transmitter,

first and second data receivers, and

wherein said transmitter being connected to a first shared unidirectional transmission path between said centralized controller and said stations for transmitting unidirectionally from said centralized controller to said stations,

wherein said first receiver being connected to a second shared unidirectional transmission path between said centralized controller and said stations for receiving data transmitted unidirectionally only from said stations to said centralized controller, and

wherein said second receiver being connected to a third shared unidirectional transmission path between said centralized controller and said stations for receiving data transmitted unidirectionally only from said stations to said centralized controller,

a second circuit for detecting whether a collision has occurred in a particular time-slot on said second path due to simultaneous transmissions on said time-slot from two or more stations, and for causing, in response to detecting said collision, said transmitter to transmit on said first path a notification to at least said stations where said collision has occurred.