Virtual clear channel avoidance (CCA) mechanism for wireless communications
AssigneeTexas Instruments Incorporated
InventorsYonghe Liu, Xiaolin Lu
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Abstract
An arrangement avoids contention on a communication medium among devices including at least a transmitter and a receiver. The arrangement involves a first portion configured to instruct a receiver to indicate that the communication medium is busy for a time period substantially longer than an actual frame transmission period being sent from the transmitter to the receiver, and a second portion configured to prohibit the receiver from transmitting on the communication medium during the time period.
Claims17
A system comprising:
- a high-throughput (HT) device configured to invoke a virtual clear channel assessment (VCCA) mechanism and set a virtual clear channel assessment (VCCA) time period equaling a sum of:
- a content of a Duration field in frame header of the frame being transmitted;
- eight times a quotient of an actual length, in octets, of the frame being transmitted, and a transmission rate, in Mbps, of the frame being transmitted;
- an extended inter frame space;
- and
- a distributed inter frame space;
- a receiving station (STA) configured to receive an indicate that the communication medium is busy for a time period equal to the virtual clear channel assessment (VCCA) time period longer than an actual frame transmission period being sent from the transmitter to the receiver;
- and
- wherein the receiving station (STA) is further configured to refrain from transmitting on the communication medium during the time period.
A method for avoiding contention on a communication medium by devices including at least a transmitter and a receiver, the method comprising:
- setting a time period equal to a virtual clear channel assessment (VCCA) time period equaling a sum of:
- a content of a Duration field in frame header of the frame being transmitted;
- eight times a quotient of an actual length, in octets, of the frame being transmitted, and a transmission rate, in Mbps, of the frame being transmitted;
- an extended inter frame space;
- and
- a distributed inter frame space;
- instructing a receiver to indicate that the communication medium is busy for the time period longer than a frame being sent from the transmitter to the receiver;
- and
- prohibiting the receiver from transmitting on the communication medium during the time period.
A network including a communication medium on which contention is to be avoided, the network comprising:
- a transmitting element, configured to transmit on the communication medium, a frame that includes an instruction that the communication medium is busy for a time period equal to a virtual clear channel assessment (VCCA) time period longer than an actual transmission time of the frame that includes the instruction equaling a sum of:
- a content of a Duration field in frame header of the frame being transmitted;
- eight times a quotient of an actual length, in octets, of the frame being transmitted, and a transmission rate, in Mbps, of the frame being transmitted;
- an extended inter frame space;
- and
- a distributed inter frame space;
- and
- a receiving element, configured to receive the frame that includes the instruction, and, in response to the instruction, to refrain from transmitting on the communication medium during the time period, so as to avoid the contention on the communication medium.
Dependencies are inferred from the claim text.