Apple Inc.

Photonics Corporation

Other

Stanley L Fickes

John N Piccone

Richard C Allen

Bernard E Stewart

Edward W Geiger

Walter S Johnson

Richard W Mincher

James L Konsevich

Gary M Cisneros

Gary N Hughes

Robert J Grady

Rick L Reagan

Jeffrey L Mullins

Aspects for achieving and utilizing synchronization among end stations in a wireless local area network (WLAN) are provided. In a method aspect, the method includes receiving a packet with a time synchronization field value from a first end station in a second end station of a communication group. The method further includes comparing upon receipt of the packet the time synchronization field value with a local time value in the second end station to determine whether the local time value requires updating to maintain synchronization between the first and second end stations. The comparing further determines whether a difference between the time synchronization field value and the local time value is greater than zero, and when the difference is greater than zero, the local time value is updated to the time synchronization field value. In a system aspect, the system includes at least two end stations, wherein each of the at least two end stations further includes a local clock unit, and a transmit/receive control unit coupled to the local clock unit. A time synchronization field register in the transmit/receive control unit stores a value of the local clock unit, with one of the at least two end stations comparing a time synchronization field register value of a packet upon receipt from another of the at least two end stations with a value of the local clock unit to determine whether updating of the local clock unit is necessary.

Method and system for synchronization in a wireless local area network

Method and system aspects for increasing throughput in a WLAN are provided. In a method aspect, a packet is transmitted from a first end station in the WLAN, the packet including an indication of a next end station in a chain of end stations having data ready for transmission in the WLAN. The method further includes transferring control of access before a predetermined time period has been exceeded to the next end station in the chain of end stations based upon the indicator. In addition, the method includes maintaining access to the network for a plurality of cooperating end stations established through continuous indication of the next end station in the chain of end stations without exceeding a maximum access time. In a system aspect, the system includes a first end station, the first end station transmitting a packet in the WLAN, and a second end station in a chain end stations cooperating with the first end station and acknowledging the packet from the first end station before a predetermined time period has been exceeded, the second end station identifying a next end station in the chain end of end stations to have access in the WLAN. Further, transmission access to the WLAN continues with the next end station in the chain end stations when the predetermined time period is not exceeded between transmitting and acknowledging.

Method and system for increasing throughput in a wireless local area

A diffuse infrared communication link provides for communication directly between nodes each having a transceiver. A repeater may be present to facilitate communication. Each node is automatically reconfigurable between operation with or without a repeater. When a repeater is present each node automatically ignores any transmission by another node.

Infrared communication repeater architecture

An infrared RS 232 communication link protocol is particularly suited for correcting any errors introduced during a transmission of information. The information is transmitted from a transmitting station to a receiving station. Each of the stations has a control counter each of which toggles between a logic 0 and 1. The control counter for the transmitter and the receiver are phase locked so that all errors may be corrected. The receiver echoes each data bit back to the transmitter which compares the echoed data to the transmitted data. If there is a match, the transmission was successful. If there is no match, the data must be retransmitted. A retransmit control character RTXx is sent to indicate that the receiver should discard the previous character and prepare for a retransmission of the character having the error. Under the proper circumstances and if the counters are still phase locked, the receiver then discards the previously stored character and inverts the counter. If the receiver detects that it has received an erroneous character, such as one having multiple or no PPM pulses, the receiver will simply respond with the reject control character REJ. In such a case, the transmitter will respond with an RTXx which causes the receiver to discard the previously stored character and invert the counter.

Link protocol for RS 232 communications

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San Jose, CA, United States of America

Stanley L Fickes