摘要:
In a wireless TDMA network a control module (CM) sends a time stamp relative to the beginning of its frame in a synchronization packet allowing each of a plurality of user modules (UM) to maintain synchronization relative to the CM. The CM uses a plurality of directional antennas and transmits the synchronization packets over each antenna over a predetermined number of frames. The UMs use a receive time stamp to identify the beginning of a received synchronization packet. The difference between the time stamps combined with a delay constant is used by the UMs to adjust time synchronization to the CM frame.
摘要:
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.
摘要:
A hierarchical addressing technique is employed in a packet communications system to enhance flexibility in storing and referencing packet information. This method permits packet message data and certain packet control data to be stored in memory locations 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 received or to be transmitted.
摘要:
An antenna selection technique is used in an RF communication 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 both signal quality and strength, the UM selects its antenna and the best node antenna for use.
摘要:
An RF communication system contains a control module which communicates with a plurality of user modules that are each connected to at least one user device. The system provides a method for packet communications in which traditional destination addressed packets are communicated to the specified destination point or user module while also permitting information intended for a plurality of user modules to be broadcast simultaneously to all user modules using a broadcast protocol. The probability of each UM receiving the broadcast packet is enhanced by the transmission by the control module of each broadcast packet over at least several of its directional antennas and preferably repeated over each antenna a number of times. Packets of data which are longer than a predetermined number of bytes are broken into packet fragments.
摘要:
A common communication controller is linked to a plurality of peripheral devices by a network interface bus. Packets containing information is communicated between the controller and the peripherals over the bus which consists of a parallel packet bus and a plurality of control lines utilized to implement a communication protocol which increases the efficiencies of packet communications by the utilization of additional direct command lines between the communications controller and peripherals.
摘要:
An improved network interface architecture for a packet switch provides for the combination of both voice and data in a single switch using a common packet structure. It allows for the dynamic allocation of bandwidth based on system loading. This includes not only bandwidth within the voice or data areas of the frame, but also between the voice and data portions. The network interface (NI) provides a mechanism (the NI-Bus) of passing all packets through the Network Interface or allowing the packet devices to directly transfer packets between one another. The bandwidth allocation can easily be changed because the control and data memories are synchronized to one another. The network interface architecture, according to the invention, allows for the data packets and the control of bandwidth allocation to be controlled by a single switching device. It synchronizes the transfer of the data and the allocation of bus bandwidth. The control of the packet devices can be controlled at a very high bit rate such as, for example, 40 Mbps. It also allows packet devices to directly transfer packets. It allows for easy re-allocation of bandwidth through the use of the NI Base Registers.
摘要:
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.
摘要:
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.
摘要:
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.