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.

Abstract: An intelligent communcations node is capable of dynamically selecting frequency and time slot assignments for communications with remote communication devices having different communication protocols including different available frequencies and time slots in a TDMA system. A frequency agile transmitter and receiver combined with an adaptable time slot selector enables communications with remote devices utilizing different protocols. The time and frequency management capabilities of the node makes greater spectral efficiencies possible.

Abstract: In a network of interconnected wireless networks and wired telephone networks, there is provided a mechanism for sustained association of users with communications paths. It comprises: upon an attempted use of an unassociated telephone, identifying oneself to the network (via the wireless network) and activating one's telephone line by keying one's own telephone number through the telephone keypad, locating his telephone line by monitoring unassociated lines for activity, and the one so identified receiving a sustaining association (for more than a few communications) with the telephone line so located.

Abstract: A method and apparatus for performing the asynchronous reconstruction of a digital data stream is disclosed. An input data stream having an input rate, such as digitized speech, is stored in a circular buffer. Within the buffer, read and write marker positions are determined. Upon subsequent retrieval of the data stream at an output rate, data is taken from the position of the read marker each time data is written to the position of the write marker. Of importance, the read and write marker positions are determined such that they provide a delay greater than the difference between the input rate and the output rate over the length of the buffer. The data stream processing is then modified by ignoring at least some of the data stream when the input rate is faster than the output rate, and repeating at least some of the data stream when the input rate is slower than the output rate. In this manner a method of digitized voice reconstruction without reliance upon network synchronizatin is achieved.

Abstract: A communication system for relatively high data bit rate RF communication overcomes multipath interference by employing relatively narrow beam antenna sectors and by selecting the best communication path established between two terminals, at least one of which has narrow beam antenna sectors. The communication path selection process includes determining the signal integrity of data communicated between the terminals. One implementation includes the narrow beam antenna sectors at each terminal.

Abstract: There is provided a scheme for bit error rate detection. It comprises: detecting the bit value present in a received multi-level signal, more narrowly detecting the bit value present in that received multi-level signal, comparing the results of narrow detection with the results detected otherwise to identify errors in detection, and accumulating detected symbol errors over unit time. Bit error rate detection can be used for antenna selection--selecting one of a plurality of diversity antennas when the error rate exceeds a certain error threshold.

Abstract: An encryption circuit that operates with substantially zero delay. Using programmable keys and polynomials, the encryption algorithm can be constantly changed to thwart any unintended receiving parties from decoding the data. A key (101) and a polynomial (102) are loaded into registers. The key is then loaded into a shift register and shifted through XOR gates (106) at a programmable rate. The other input of the XOR gates come from the result of ANDing (103) a disable signal, the polynomial register (102), and the last stage of the shift register (104). Eight bits of the shift register outputs are XOR'ed with the input data to be encrypted. The output of these XOR gates (105) is the encrypted data.

Abstract: An antenna is disclosed for increasing the gain of, or shaping the pattern of, a radiated radio frequency signal. The antenna includes a waveguide for directing the radio frequency signal or for receiving directively the radio signal, a first conductive reflector disposed beneath the waveguide and extending beyond the aperture of the waveguide for reflecting certain of the waves emanating from or entering the aperture of the waveguide, and a second reflector, which may be the mounting surface, disposed beneath the first reflector and extending beyond the first reflector for reflecting other of the waves emanating from or entering the aperture of the waveguide.

Abstract: A data communications system (100) that communicates messages by way of a radio frequency (RF) channel between a network control processor (NCP 102) and subscriber radios (190) located anywhere in a large geographical area that is divided into a plurality of cells or zones, each of which is covered by one or more base station radios (130-132). Base station radios (130-132) and a control station radio (140) are coupled by corresponding general communications controllers (GCCs 120-123) and modems (108-111) via links (150-152) to modems 104-107) coupled to the NCP (102). The control station radio (140) transmits a set-clock message (610) to GCCs (120-122) associated with each of the base station radios (130-132). Each GCC (120-122) is responsive to receipt of the set-clock command for updating its clock (214). Each data message (600) to be transmitted to the subscriber radios (190) may be substantially simultaneously transmitted or "simulcasted" at a pre-selected time.

Abstract: A unique cellular data telephone system includes a cellular telephone system (CTS 150), a cellular data switch (CDS 170), and a telephone central office (130) for providing both voice and data telephone servies to portable and mobile cellular data telephone (CDTs 102, 122) located anywhere in a large geographical area. Each of the CDTs (102, 122) includes a data control unit (DCU 106), a cellular modem (162) and a cellular telephone (108) and associated antenna (110), and connects to a data terminal (104, 124) with keyboard and display.

Abstract: A data communications system covers a geographic area divided into a plurality of non-overlapping zones and includes a general communications controller (GCC), a plurality of channel communications modules (CCM) and associated transmitters and receivers, and a plurality of portable radios. Messages carrying alphanumeric information are communicated between the GCC and the portable radios by way of a radio channel. Each CCM takes a signal strength measurement every time it receives a message from a portable radio. The GCC includes a multi-tasking processor that executes tasks on a priority basis. Inbound messages are processed on a high priority basis and are ignored if the GCC is overloaded and the inbound message is of the type that will be reasserted. Thus, by shedding inbound messages that will be re-asserted, the GCC can accomodate peak message loads demanding 100% of its capacity without becoming unstable.

Abstract: A method and apparatus for coordinating the transfer of communications control from one independent radio communications system to another is disclosed. A remote unit which communicates data messages is associated with a home system which has a plurality of fixed sites and overlapping radio coverage areas. As the remote unit travels away from its home system, communications may be maintained by providing radio coverage from an independent roam system. The last message received by the home and roam systems from the remote unit has the associated radio signal strength and time of reception stored at each system. When a current message is transmitted by the remote unit and both the home and the roam system receive the message, the roam system time stamps the message and calculates the signal strength associated with the current message.

Abstract: A data signalling system for transmitting signals between at least one primary station and a plurality of secondary stations. The system is well adapted for use in multiple unit radio communications systems capable of noise and data communications. A register model is utilized which permits a highly flexible signalling system compatable with a wide range of communications networks. Data transfer is accomplished using fixed length data packets which are error correction encoded and transmitted utilizing PSK modulation.

Abstract: A data communications system is described that covers a geographic area divided into a plurality of non-overlapping zones and includes a general communications controller (GCC), a plurality of channel communications modules (CCM) and associated transmitters and receivers, and a plurality of portable radios. Message signals carrying alphanumeric information are communicated between the GCC and the portable radios by way of a radio channel. Each CCM has at least one transmitter and receiver for covering at least one zone. Each CCM receiver has a coverage area overlapping the coverage area of at least two other CCM receivers and at least a predetermined minimum probability P of successful reception of a transmission from a data radio located in its coverage area, such that the joint probability P.sub.J of successful reception of the transmission from the portable radio by at least one of the CCM receivers is expressed by the equation, P.sub.J =1-(1-P).sup.3.

Abstract: A data signalling system for transmitting signals between at least one primary station and a plurality of secondary stations. The system is well adapted for use in multiple unit radio communications systems capable of noise and data communications. A register model is utilized which permits a highly flexible signalling system compatable with a wide range of communications networks. Data transfer is accomplished using fixed length data packets which are error correction encoded and transmitted utilizing PSK modulation.

Abstract: An adaptable homotropic antenna system for use with a portable communication transceiver is described. The antenna system can be used for reception or transmission and can be completely enclosed within the portable transceiver housing. The homotropic antenna system evaluates the quality of a received signal and if the signal is below a predetermined threshold level, an alternate antenna will be selected. The antenna system will continue to sample the available antennas until an antenna produces a signal of acceptable quality.

Abstract: A data communications system is described that covers a geographic area divided into a plurality of non-overlapping zones and includes a general communications controller (GCC), a plurality of channel communications modules (CCM) and associated transmitters and receivers, and a plurality of portable radios. Message signals carrying alphanumeric information are communicated between the GCC and the portable radios by way of a radio channel. Each CCM takes a signal strength measurement every time it receives a message signal from a portable radio. The GCC gathers the signal strength measurements from the CCM receivers receiving the same message signal and computes an adjusted signal strength for each zone. The GCC then selects the zone having the largest adjusted signal strength for determining the location of the portable radio that transmitted the message signal.