Constant bit rate transport in a contention based medium access control
First Claim
1. A method employed in a two way communications system comprising a controller and a plurality of user terminals, the two way communications system capable of carrying information flows and bursts of data of the plurality of user terminals, the controller transmitting downstream information to the plurality of user terminals on at least one downstream channel, the plurality of user terminals transmitting upstream information to the controller on at least one shared upstream channel of a shared communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, at least one media access control mechanism being used to resolve contention for transmission on the at least one shared upstream channel, an upstream information transmission of at least one first user terminal of the plurality of user terminals capable of colliding on the at least one shared upstream channel with an upstream information transmission of at least one second user terminal of the plurality of user terminals, the method comprising the steps of:
- processing a reservation request that solicits a first grant of at least one first upstream time slot to carry a requested burst of data, the requested burst of data having a requested burst size of finite amount;
maintaining a list of at least one information flow, the list of at least one information flow being associated with at least one service parameter;
scheduling a second grant of at least one second upstream time slot, the scheduling being based at least upon a first entry in the list of the at least one information flow and the at least one service parameter, the second grant being scheduled to provide a first information flow with a quality of service indicated by the at least one service parameter, the first information flow being associated with the first entry in the list of at least one information flow;
sending notice of the first grant to the plurality of user terminals responsive to the reservation request that solicits the first grant, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and
sending notice of the second grant to the plurality of user terminals responsive to the scheduling of the second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow.
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Accused Products
Abstract
In a two way cable system that includes a controller and a plurality of user terminals, a method of granting rights for upstream data transmission from the user terminals includes processing contention requests to generate contention grants and maintaining a list of connections, each connection having specified therefor a predetermined bit rate. The controller sends a downstream data stream to the user terminals and receives an upstream data stream from the user terminals. The downstream data stream includes a plurality of grant fields, and the upstream data stream includes upstream data slots and upstream control slots. The method further includes scheduling preemptive grants for upstream data slots using selected fields of the plurality of grant fields so as to provide preemptive grants for upstream data transport at a bit rate specified for each connection, sending to the user terminals a data transmission grant in a grant field of the plurality of grant fields for which a preemptive grant is scheduled, and sending to the user terminals a data transmission grant in a grant field of the plurality of grant fields in which a contention grant is pending and no preemptive grant is scheduled.
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Citations
146 Claims
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1. A method employed in a two way communications system comprising a controller and a plurality of user terminals, the two way communications system capable of carrying information flows and bursts of data of the plurality of user terminals, the controller transmitting downstream information to the plurality of user terminals on at least one downstream channel, the plurality of user terminals transmitting upstream information to the controller on at least one shared upstream channel of a shared communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, at least one media access control mechanism being used to resolve contention for transmission on the at least one shared upstream channel, an upstream information transmission of at least one first user terminal of the plurality of user terminals capable of colliding on the at least one shared upstream channel with an upstream information transmission of at least one second user terminal of the plurality of user terminals, the method comprising the steps of:
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processing a reservation request that solicits a first grant of at least one first upstream time slot to carry a requested burst of data, the requested burst of data having a requested burst size of finite amount; maintaining a list of at least one information flow, the list of at least one information flow being associated with at least one service parameter; scheduling a second grant of at least one second upstream time slot, the scheduling being based at least upon a first entry in the list of the at least one information flow and the at least one service parameter, the second grant being scheduled to provide a first information flow with a quality of service indicated by the at least one service parameter, the first information flow being associated with the first entry in the list of at least one information flow; sending notice of the first grant to the plurality of user terminals responsive to the reservation request that solicits the first grant, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and sending notice of the second grant to the plurality of user terminals responsive to the scheduling of the second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68)
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69. A controller in a two way communications system comprising the controller and a plurality of user terminals, the two way communications system capable of carrying information flows and bursts of data of the plurality of user terminals, the controller transmitting downstream information to the plurality of user terminals on at least one downstream channel, the plurality of user terminals transmitting upstream information to the controller on at least one shared upstream channel of a shared communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, at least one media access control mechanism being used to resolve contention for transmission on the at least one shared upstream channel, an upstream information transmission of at least one first user terminal of the plurality of user terminals capable of colliding on the at least one shared upstream channel with an upstream information transmission of at least one second user terminal of the plurality of user terminals, the controller comprising:
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logic configured to process a reservation request that solicits a first grant of at least one first upstream time slot to carry a requested burst of data, the requested burst of data having a requested burst size of finite amount; logic configured to maintain a list of at least one information flow, the list of at least one information flow being associated with at least one service parameter; logic configured to schedule a second grant of at least one second upstream time slot, the scheduling being based at least upon a first entry in the list of the at least one information flow and the at least one service parameter, the second grant being scheduled to provide a first information flow with a quality of service indicated by the at least one service parameter, the first information flow being associated with the first entry in the list of at least one information flow; logic configured to sending send notice of the first grant to the plurality of user terminals responsive to the reservation request that solicits the first grant, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and logic configured to sending send notice of the second grant to the plurality of user terminals responsive to the scheduling of the second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow. - View Dependent Claims (70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92)
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93. A method employed in a two way communications system comprising a controller and a plurality of user terminals, the two way communications system capable of carrying information flows and bursts of data of the plurality of user terminals, the controller transmitting downstream information to the plurality of user terminals on at least one downstream channel, the plurality of user terminals transmitting upstream information to the controller on at least one shared upstream channel of a shared communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, at least one media access control mechanism being used to resolve contention for transmission on the at least one shared upstream channel, an upstream information transmission of at least one first user terminal of the plurality of user terminals capable of colliding on the at least one shared upstream channel with an upstream information transmission of at least one second user terminal of the plurality of user terminals, the method comprising the steps of:
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sending a reservation request that solicits a first grant of at least one first upstream time slot to carry a requested burst of data, the requested burst of data having a requested burst size of finite amount; maintaining a first information flow, the first information flow being associated with at least one service parameter, the first information flow having a quality of service indicated by the at least one service parameter; receiving notice of the first grant from the controller responsive to the reservation request that solicits the first grant, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and receiving notice of a second grant from the controller responsive to the controller scheduling of a second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow. - View Dependent Claims (94, 95, 96, 97, 100, 101, 102, 103, 104)
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- 98. The method of clam 93, wherein the upstream time slots comprise a first type of upstream time slots and a second type of upstream time slots, the first type of upstream time slots limited to carrying reservation requests, and the second type of upstream time slots capable of carrying data that is not limited to reservation requests.
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105. A method employed in a two way communications system comprising a controller and a plurality of user terminals, the two way communications system capable of carrying information flows and bursts of data of the plurality of user terminals, the controller transmitting downstream information to the plurality of user terminals on at least one downstream channel, the plurality of user terminals transmitting upstream information to the controller on at least one shared upstream channel of a shared communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, at least one media access control mechanism being used to resolve contention for transmission on the at least one shared upstream channel, an upstream information transmission of at least one first user terminal of the plurality of user terminals capable of colliding on the at least one shared upstream channel with an upstream information transmission of at least one second user terminal of the plurality of user terminals, the method comprising the steps of:
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maintaining a first information flow, the first information flow being associated with at least one service parameter, the first information flow having a quality of service indicated by the at least one service parameter; receiving notice of a first grant from the controller responsive to the controller scheduling of the first grant, the first grant message indicating an allocation of at least one first upstream time slot to carry data that is at least part of the first information flow; and disregarding notice of a second grant from the controller, the notice of the second grant indicating the allocation of a second grant of at least one second upstream time slot to the at least one second user terminal, the second grant generated by the controller responsive to the at least one second user terminal sending a reservation request that solicits the second grant to carry a requested burst of data, the requested burst of data having a requested burst size of finite amount. - View Dependent Claims (106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116)
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117. A method for scheduling data transmissions, wherein the method is employed in a two-way communications system comprising a controller and a plurality of stations, the two-way communications system capable of carrying information flows and bursts of data of the plurality of stations, the controller transmitting downstream information to the plurality of stations on at least one downstream channel, the plurality of stations transmitting upstream information to the controller on at least one shared upstream channel of the communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, the method comprising:
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processing a request for recurring time slots that includes soliciting a first grant of at least one first upstream time slot the at least one shared upstream channel of the communications medium, the at least one shared upstream channel capable of carrying an upstream transmission from a first station, the transmission capable of colliding with an upstream transmission from at least one second station, the time slots for carrying bursts of data having a burst size of finite amount; scheduling a plurality of unsolicited upstream transmission grants comprising a second grant of at least one second upstream timeslot, the scheduling being based at least upon a first entry in a list of at least one information flow and at least one service parameter, the second grant being scheduled to provide a first information flow with a quality of service indicated by the at least one service parameter, the first information flow being associated with the first entry in the list of at least one information flow; sending notice of the first grant to the plurality of stations responsive to the request for recurring time slots, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and sending notice of the second grant to the plurality of stations responsive to the scheduling of the second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow. - View Dependent Claims (118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131)
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132. A controller in a two-way communications system comprising a controller and a plurality of stations, the two-way communications system capable of carrying information flows and bursts of data of the plurality of stations, the controller transmitting downstream information to the plurality of stations on at least one downstream channel, the plurality of stations transmitting upstream information to the controller on at least one shared upstream channel of the communications medium, the bandwidth of the at least one shared upstream channel being divided into upstream time slots, the upstream time slots capable of carrying reservation requests and data, the controller comprising:
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logic configured to process a request for recurring time slots that includes soliciting a first grant of at least one first upstream time slot in the at least one shared upstream channel of the communications medium, the at least one shared upstream channel capable of carrying an upstream transmission from a first station, the transmission capable of colliding with an upstream transmission from at least one second station, the time slots for carrying bursts of data having a burst size of finite amount; logic configured to schedule a plurality of unsolicited upstream transmission grants comprising a second grant of at least one second upstream timeslot, the scheduling being based at least upon a first entry in a list of at least one information flow and at least one service parameter, the second grant being scheduled to provide a first information flow with a quality of service indicated by the at least one service parameter, the first information flow being associated with the first entry in the list of at least one information flow; logic configured to send notice of the first grant to the plurality of stations responsive to the request for recurring time slots, the notice of the first grant indicating an allocation of the at least one first upstream time slot to carry a granted burst of data, the granted burst of data having a granted burst size and comprising a finite amount of data; and logic configured to send notice of the second grant to the plurality of stations responsive to the scheduling of a second grant, the notice of the second grant indicating an allocation of the at least one second upstream time slot to carry data that is at least part of the first information flow. - View Dependent Claims (133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146)
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Specification