Abstract:
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.
Abstract:
An antenna selection technique is used in an RF communication system in which user modules (UM1-UM5) communicate with at least one node (N1-N2). The UM's (UM1-UM5) and nodes (N1, N2) each have multiple antennae. The combination of each UM and node antenna is evaluated at the UM. Based on at least signal quality, the UM (UM1-UM5) selects its antenna and the best node antenna for use. An alternate antenna is selected if a person is determined to be present in a predetermined area adjacent a UM (UM1-UM5) corresponding to a predetermined RF power level.
Abstract:
In this invention a hierarchical addressing technique is employed in a packet communications system to enhance flexibility in handling packet information. This method permits packet message data (Fig. 3) and certain packet control data (Fig. 3) to be stored in memory locations (32, 34) without having to be duplicated at a different memory location prior to transmission of the packet. This method is preferably employed in a ring configuration in which a series of packets have addressing mechanisms which points sequentially to each other to form a ring of packets.
Abstract:
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 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 compared and stored in an order determined by the sequence information when the sequence numbers do not compare.
Abstract:
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 (T1) 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.
Abstract:
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.
Abstract:
An antenna selection technique is used in an RF communication system in which user modules (UM1-UM5) communicate with at least one node (N1-N2). The UM's (UM1-UM5) and nodes (N1, N2) each have multiple antennae. The combination of each UM and node antenna is evaluated at the UM. Based on at least signal quality, the UM (UM1-UM5) selects its antenna and the best node antenna for use. An alternate antenna is selected if a person is determined to be present in a predetermined area adjacent a UM (UM1-UM5) corresponding to a predetermined RF power level.
Abstract:
An antenna selection technique is used in an RF communication system in which user modules (UM1-UM5) communicate with at least one node (N1-N2). The UM's (UM1-UM5) and nodes (N1, N2) each have multiple antennae. The combination of each UM and node antenna is evaluated at the UM. Based on at least signal quality, the UM (UM1-UM5) selects its antenna and the best node antenna for use. An alternate antenna is selected if a person is determined to be present in a predetermined area adjacent a UM (UM1-UM5) corresponding to a predetermined RF power level.
Abstract:
In this invention a hierarchical addressing technique is employed in a packet communications system to enhance flexibility in handling packet information. This method permits packet message data (Fig. 3) and certain packet control data (Fig. 3) to be stored in memory locations (32, 34) without having to be duplicated at a different memory location prior to transmission of the packet. This method is preferably employed in a ring configuration in which a series of packets have addressing mechanisms which points sequentially to each other to form a ring of packets.
Abstract:
An antenna selection technique is used in an RF communincation system in which user modules (UM) communicate with at least one node. The UM's and nodes each have multiple antennae. The combination of each UM and node antenna is evaluated at the UM. Based on at least signal quality, the UM selects its antenna and the best node antenna for use. An alternate antenna is selected if a person is determined to be present in a predetermined area adjacent a UM corresponding to a predetermined RF power level.