Motorola Corporation

Christopher L Clanton

Jeffrey C Smolinske

Phieu M Tran

Robert C Scheibel, Jr

Phieu Moc Tran

Louis D Finkelstein

Jeffrey T Klayman

Robert C Scheibel

The apparatus (101, 110) and method for authentication is provided by generating R and encrypting it using a selected algorithm K as the key in a primary station, encrypting the verification key, V using R as the key and encrypting the result using K as the key, transmitting both pieces of information (VAR1 and VAR3) to the secondary station (110), using K to decrypt VAR1 and VAR3 to obtain R and eventually V which is encrypted using R in the secondary station (110)verifying authenticity of the primary station (101) if the decrypted V matches the secret key portion of V that is stored at the secondary station (110).

Apparatus and method for authentication and session key exchange in a

The present invention provides a method (500), device (400), microprocessor (500) and microprocessor memory (400, 500, 600) for instantaneous preemption of packet-switched data from a user that has won contention for a channel and for transmitting on a time slot, by higher priority traffic type data or voice in a TDMA communication system having a central access manager and a plurality of subscriber units. Before transmitting a packet on an uplink channel, the subscriber unit first selects a time slot and contends for channel access on the time slot. Upon gaining access to the uplink channel, the subscriber unit begins transmitting segments of a data packet on the selected time slot, suspending transmission when a higher priority user gains access to the time slot and, where decoding fails, suspending transmission for the time slot. The subscriber unit continues to transmit on the selected time slot until the packet ends.

Method, device, microprocessor and microprocessor memory for

The method and device of the present invention provide for efficient error correction in a packet radio system by 1) eliminating wasted bandwidth due to the unnecessary retransmissions that occur as a result of lost positive acknowledgments, 2) occupying less downlink bandwidth than a scheme requiring positive acknowledgments, and 3) minimizing packet delay by providing two levels of error correction at the datalink layer.

Method and device for efficient error correction in a packet-switched

The present invention provides a method (400, 500, 600, 700, 800, 900, 1000) and device (1100, 1200, 1300) for contention for channel access to single-slot subscriber units that are capable of transmitting and receiving data on one time slot per TDMA frame, allowing contention for channel access on any one of the available packet time slots and transmission on the time slot where contention is won. Thus, the present invention eliminates a requirement for a subscriber unit to be assigned to a particular time slot for contention, thereby eliminating the problem of performing load balancing on the time slots.

Method and device for channel contention and data transmission for

A novel scheme efficiently indicates to a plurality of users which user has been granted access to a multi-access packet channel. Transmission and reception of a predetermined limited number of echo bits per timeslot reduces bandwidth usage, and over the duration of a packet, these bits are equivalent to a variable length random identification number which is used for identifying which user has been granted access.

Method and system for resolution of channel access in data transmission

The present invention provides a unique access control scheme for assigning a plurality of time slots in a fair manner among subscriber units using a single time slot in a frame and subscriber units using multiple time slots in a frame in a communication system.

Method and device for controlling time slot contention to provide

Collision avoidance is maximized by placing collision avoidance scheduling in a central access manager. The central access manager coordinates downlink transmissions of a base site with the uplink transmissions by subscriber units, virtually avoiding collisions of the two types of transmissions. The subscriber units utilize a waiting period prior to transmission of packets to permit the central access manager to maintain the scheduling.

Method and system for providing uplink/downlink collision avoidance in a

The method reduces transmission delay by using a selective-repeat automatic repeat request, ARQ, error detection scheme in a packet-switched data communication system. The invention provides a method for a subscriber unit to transmit acknowledgment information using a contention-free channel access scheme in addition to providing for a base site control unit to interrupt a packet currently being transmitted in order to retransmit segments of the packet when the segments have errors.

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Chicago, IL, United States of America

Christopher L Clanton