Motorola Corporation

R Lee Hamilton, Jr

Dale Robert Buchholz

William K Doss

Karen E Robbins

Richard E White

Mark A Yednak

A packet transmission system (100) with reduced transmission delays includes a communications controller (110) and a plurality of remote requesting units (112) requesting packet transmission services. Each remote unit (112) sequentially stores transmitted access requests (302) in a memory queue (500) and awaits a resource grant (306) from the communications controller (110). Upon receipt of a granted resource the remote unit (112) will apply the granted resource to the oldest request (502) stored in the queue (500) in order to transmit data (310) to the communications controller (110). A separate and distinct aspect of the transmission system (100) resides within the communications controller (110). In response to the receipt of a data packet (310) from a remote unit (112), the communications controller (110) identifies missing data within the data packet transmission, determines whether communication resources are available to support retransmission of the missing data, and if so, transmits a response to the requesting remote unit identifying the missing data and simultaneously granting sufficient resources for retransmission of the missing data.

Method for reducing transmission delays in a packet transmission system

A packet transmission system (100) for reducing request traffic contention and the likelihood of resource misallocation includes a communications controller (110) and a plurality of remote requesting units (112) requesting packet transmission services. In response to receipt of a request (302), the controller (110) transmits a grant (306) to a requesting unit (112) when packet transmission resources (304 & 310) are available or a request acknowledgment (306) when packet transmission resources (304 & 310) are unavailable. Each remote unit (112) comprise apparatus structure and method steps for transmitting requests (302) to the controller (110) and starting a first timer having an interval (T) determined as a function of a number (Q) of outstanding requests (302). Upon receipt of an acknowledgement (306), the remote unit (112) starts a second timer having an interval (T.sub.1) longer than the interval (T). Upon expiration of either the first timer or the second timer, the remote unit (112) will then and only then transmit a duplicate request (302). By limiting the number of duplicate requests transmitted by a remote unit (112), the present invention operates to reduce request traffic contention and the likelihood of resource misallocation.

Method and apparatus for reducing the likelihood of contention and

A packet switching system (100) having a packet switch (140) employs an acknowledgement scheme in order assure the delivery of all fragments (310) comprising a fragmented data packet (300) to improve overall system throughput during the handling of packets (310) that require reassembly. When packet fragments (310) are lost, corrupted or otherwise unintelligible to a receiving device (92, 94), the acknowledgement scheme permits retransmission of the missing data. In addition, a second acknowledgment signal is scheduled by system processing resources (110) in order to verify the successful delivery of all retransmitted data.

Packet delivery system

Transmission of broadcast packets (46) in a radio frequency (RF) communication system between a control module (22) and user modules (20), wherein the control module (22) and the user modules (20) each have a plurality of antennae (A1-A6) includes generating a list (1100) of control module antennae (A1-A6) in radio communication with at least one of said plurality of user modules; and selecting the listed control module antennae for transmission of broadcast packets (46).

Transmission of broadcast packets in an RF system

A method and apparatus for preserving the sequential relationship of a plurality of data packets 310 generated by separate source devices 14 and ordered as a data stream 300, despite transmission over radio channels which introduce ordering errors comprises method steps and apparatus structure for identifying at a first terminal, data packets from within the data stream as a function of source, generating data packet sequence information for identified data packets, storing values corresponding to data packet sequence numbers as a function of source and transmitting data packets, source device identity and packet sequence information to a second terminal having first terminal source device and data packet sequence information. Upon receipt of a first terminal transmission, the second terminal retrieves from second terminal memory, first terminal data packet sequence information and compares the stored data packet sequence information with received data packet sequence information. As a function of the comparison, received data packets are forwarded to an appropriate application for further processing when sequence information sequence numbers compare and stored in an order determined by the sequence information when the sequence numbers do not compare.

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Palatine, IL, United States of America

R Lee Hamilton, Jr