Antenna control for a wireless local area network station
First Claim
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1. A local area network station comprising:
- transceiver means to operate on a wireless electromagnetic wave transmission channel, hereinafter referred to as channel, having a plurality of antennas;
communication control means operative when said channel is active to defer transmission of a data frame, referred to as a deferred data frame, for a random number of backoff slot time periods after the channel has become inactive;
said communication controller means including a CSMA/CD local area network (LAN) controller chip which is used in wired LANs, said controller chip using a simulated collision detect signal to initiate said backoff slot time periods;
antenna switch means to select one of said plurality of antennas for operative connection to said transceiver means; and
synchronizing means to control said antenna switch means to provide antenna slot time periods having durations equal to said backoff slot time periods, and also to synchronize the start of said data frame transmissions with the start of said antenna slot time periods.
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Abstract
A local area network station (12) includes a transceiver (20) adapted to transmit and receive signals using electromagnetic radiation on a wireless communication link. The station (12) utilizes a CSMA/CD communications controller (22) in a CSMA/CA (collison avoidance) technique wherein deferred data frames are transmitted after a random number of backoff slots periods. A plurality of antennas (14, 16) is employed, with the antenna having the best receive conditions being selected for reception of a data frame. The antennas having a slotting control (200) which is synchronized with the backoff slotting to provide a short carrier detect time and hence high throughpout.
147 Citations
9 Claims
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1. A local area network station comprising:
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transceiver means to operate on a wireless electromagnetic wave transmission channel, hereinafter referred to as channel, having a plurality of antennas; communication control means operative when said channel is active to defer transmission of a data frame, referred to as a deferred data frame, for a random number of backoff slot time periods after the channel has become inactive; said communication controller means including a CSMA/CD local area network (LAN) controller chip which is used in wired LANs, said controller chip using a simulated collision detect signal to initiate said backoff slot time periods; antenna switch means to select one of said plurality of antennas for operative connection to said transceiver means; and synchronizing means to control said antenna switch means to provide antenna slot time periods having durations equal to said backoff slot time periods, and also to synchronize the start of said data frame transmissions with the start of said antenna slot time periods. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of transmitting data frames in a local area network including a plurality of local area network stations, each station comprising transceiver means adapted to operate on a wireless transmission channel and a plurality of antennas, including the steps of:
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(a) determining, in each station, if said transmission channel is active and, if so, deferring transmission of a data frame by that station for a random number of equal duration backoff slot time periods after said transmission channel has become inactive through using a simulated collision detect signal in association with a CSMA/CD local area network (LAN) controller chip which is used in wired LANs; (b) providing, in each station, switching means adapted to connect said antennas in turn to said transceiver means, each for an antenna slot time period equal to one of said backoff slot time periods; and (c) synchronizing said antenna slot time periods for all of said station in said network.
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Specification