Protocol for allocating upstream slots over a link in a point-to-multipoint communication system
A system for controlling a contention state for a communication link between a base station controller and customer premises equipment in point-to-multipoint communication. The contention state is controlled using a state machine, which includes a grant pending absent state in which a unicast request slot is maintained open for use by the customer premises equipment. During the grant pending absent state, the customer premises equipment sends no upstream data to the base station controller but can use the unicast request slot to request a data slot for sending upstream data to the base station controller. In the grant pending state, the customer premises equipment preferably uses piggybacking to request grant of a next data slot while sending upstream data to the base station controller.
1. A customer premises equipment (CPE), comprising:
a processor;
an antenna operable to send information using wireless communication techniques in a point-to-multipoint communication system, the CPE operable to communicate with a base station controller (BSC) over a communication link shared with other CPEs; and
a memory comprising instructions, the instructions executable by the processor to:
operate the CPE in a grant pending state wherein
the CPE awaits receipt of a bandwidth grant from the BSC,
receives the bandwidth grant,
transmits, via the antenna, data to the BSC using the granted bandwidth,
transmits, via the antenna, a first type bandwidth request using the granted bandwidth and
transitions from the grant pending state to a grant pending absent state once
the CPE has transmitted upstream data to the BSC within a bandwidth specified by the bandwidth grant received from the BSC during the grant pending state and
the CPE has no pending bandwidth requests;
operate the CPE in the grant pending absent state wherein the CPE awaits arrival of data for transmission to the BSC and transmits, via the antenna, a second type bandwidth request to the BSC without entering into contention when the CPE receives data for transmission;
transition operation of the CPE from the grant pending absent state to the grant pending state subsequent to and in consequence of a subsequent bandwidth grant received at the CPE; and
transition operation of the CPE from the grant pending absent state to an idle state if the CPE does not transmit any second type bandwidth request to the BSC during a timeout period.
2. A CPE as claimed in claim 1 , wherein the processor ceases operating the wireless communication device in the idle state and transmits a third type message to the BSC in a contention transmission opportunity on condition that upstream data to be sent to the BSC is received.
3. A CPE as claimed in claim 2 , wherein the processor is capable of increasing a deferral time for transmission of a subsequent third type message on condition that the upstream data transmission grant is not received within the deferral time.
4. A CPE as claimed in claim 2 , wherein the third type message is transmitted in contention with messages from other CPEs in the wireless communication system.
5. A CPE as claimed in claim 1 , wherein the bandwidth grant specifies an upstream transmission resource for transmission of the upstream data to the BSC.
6. A CPE as claimed in claim 5 , wherein the first type message is transmitted to the BSC in the upstream transmission resource allocated to the CPE for transmitting the upstream data.
7. A CPE as claimed in claim 5 , wherein the processor further operates the antenna to transmit an additional first type message to the BSC within the upstream transmission resource if there is additional data pending transmission to the BSC.
8. A CPE as claimed in claim 5 , wherein the second type message indicates to the BSC that the new upstream data awaits transmission to the BSC.
9. A CPE as claimed in claim 5 , wherein the processor further operates the antenna to transmit only the first type message within the upstream transmission resource, if the upstream transmission resource cannot accommodate both the upstream data and the first type message.