Abstract: In a frequency hopped wireless network, more robust method and system are disclosed for recovering clock synchronization. The method and system of the invention relies on the fact that correct decoding of a received packet occurs only when the same clock value is used to generate the decoding sequence at both the sender and the receiver. Several decoding sequences are tried based on different clock values to decode the packet. The different clock values used may be adjacent or nearby an initial estimated clock value. The clock value of the first decoding sequence to result in a correctly decoded packet is taken as the proper clock value for synchronization. Correct decoding is determined by checking the CRC of the packet.

Abstract: A system and method for adaptive voice buffering is disclosed. In a voice transmitter, a ring buffer uses read and write pointers to implement changes in the delay of a communication link. The receiver also implements a ring buffer having read and write pointers to buffer incoming digitized voice information transmitted over the link. Delay changes may be implemented during silent periods to render delay variations in the received signal undetectable to a user of the receiver.

Abstract: A system and method for resource management and traffic control in time division duplex communication systems is discloses. A multi-radio base station maintains communication links with a plurality of remote terminals, each of which requests a specific bandwidth ratio. A controller analyzes the requested bandwidth ratios and allocates slots in the base station radios according to a packing scheme that synchronizes the transmission and receive timing of the multiple base station radios communication links.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: A wireless network includes master and slave units. The master sends a master address and clock to the slaves. Communication is by means of a virtual frequency hopping channel whose hopping sequence is a function of the master address, and whose phase is a function of the master clock. Transmitted inquiry messages solicit slave address and topology information from the slaves, which may be used to generate a configuration tree for determining a route for a connection between the master and slave units. Slave address and topology information may include an own address from each of the slave units and only first order address lists from each of the slave units. Generating the configuration tree involves generating a hierarchy of connectivity rings from the first order address lists. Each connectivity ring may be generated in accordance with a rule that a higher-numbered connectivity ring cannot include nodes representing units that are already represented by a node in a lower-numbered connectivity ring.

Abstract: A system and method for establishing ad hoc communication sessions between remote communication terminals is disclosed. A base station transmits a beacon signal including information about the identity and system clock of the base station. Remote terminals within range lock to the base station, synchronizing their system clocks with the base station's clock and setting their hop sequence and hop sequence phase based on information in the beacon signal. To establish an ad hoc communication session, a master terminal first establishes a link to the base station, which establishes a link to a desired slave terminal. The base terminal exchanges information between remote terminals that enables the master terminal to establish a direct communication session with a slave terminal.

Abstract: A method and apparatus are described for applying a narrow band FH link for low-rate and medium-rate communications, and a stationary wide band channel for high-speed (HS) communications. A master and one or more slaves sharing the same FH link may form a piconet. Master and slaves may hop synchronously according to a pseudo-random hop sequence. A master may control traffic on the FH link. An HS link can be established between a master and one or more slaves or between two slaves. An appropriate band of the radio spectrum is selected adaptively based on lowest RSSI measurements both in master and slave to establish the HS link without making use of a hopping scheme. A master shares its time between the HS slave on the HS link and the slaves remaining on the FH link using Time Division multiplexing. If the HS link uses a part of the band over which the piconet hops, the master controls the traffic such that the HS link is never visited by the FH link.

Abstract: Transmission power in a frequency-hopping radio system that transmits packets from a sending radio unit to a receiving radio unit, wherein each packet includes an address designating the receiving radio unit, is controlled by measuring received signal strength of packets whose addresses were successfully received in the receiving radio unit, regardless of whether other portions of the respective packets were successfully received. An average signal strength value is generated from the received signal strength measurements. The mathematical difference between the average signal strength value and a target value associated with the receiving radio unit is then determined and used as a basis for deciding whether to send a power control message from the receiving radio unit to the sending radio unit.

Abstract: An entire radio transceiver can be completely integrated into one IC chip. In order to integrate the IF filters on the chip, a heterodyne architecture with a low IF is used. A single, directly modulated VCO is used for both up-conversion during transmission, and down-conversion during reception. Bond-wires are used as resonators in the oscillator tank for the VCO. A TDD scheme is used in the air interface to eliminate cross-talk or leakage. A Gaussian-shaped binary FSK modulation scheme is used to provide a number of other implementation advantages.

Abstract: Networking in uncoordinated frequency hopping piconets includes forming an anchor piconet from a plurality of wireless units that are in range of one another. An anchor unit is selected from the plurality of wireless units. A beacon signal is generated from the anchor unit and the remaining wireless units are locked onto the beacon signal. An additional embodiment the invention in peer-to-peer ad-hoc networking includes establishing at least one anchor piconet and establishing at least one traffic piconet between at least two wireless units in the anchor piconet. The traffic piconet is established using information relayed from the anchor unit to each wireless unit that participates in the traffic piconet. Since the anchor unit knows routing and identification information of all the wireless units, the traffic piconets can be established with minimal delay.

Abstract: In a radio system that employs frequency hopping (FH), access time delay is reduced, without compromising processing gain, by adding direct-sequence (DS) spreading to the system. This results in a hybrid FH/DS system, wherein the use of DS spreading permits a reduction in the number of hop frequencies used during start-up. Once synchronization is achieved, pure FH spreading, rather than the hybrid FH/DS spreading, along with a greater number of hop frequencies are used.

Abstract: In packet-based communications systems, quality of voice channels in the presence of interference is improved by processing voice payload data of a data packet even if header data of the packet includes errors.

Abstract: Mobile handover between a private radio communications network connected to the public switch telephone network and a public land mobile network also connected to the public switch telephone network are provided by a radio communications mobile terminal supporting simultaneous communication connections between the two uncoordinated networks. The mobile terminal monitors a base station of the public land mobile network during idle frames of communication connections with the private radio communications network, thereby synchronizing the mobile terminal to both the base of the public land mobile network and the private radio communications network.

Abstract: A frequency hopping generator comprises an XOR processing module and a PERM (permutation) processing module arranged in series. The XOR and PERM modules act directly on input clock lines as a function of a selection address. The hopping number sequence generated by the frequency hopping generator can be changed in real-time by changing the selection addresses, while the phase of the sequence can be changed in real-time by changing the clock value on the clock lines. The frequency generator finds exemplary use in rapidly switching between different piconets in a wireless scatter network.

Abstract: A multi-carrier radio system in which pairs of subcarriers are positioned in frequency such that each subcarrier in a pair is the image of the other subcarrier in the pair. By making each subcarrier the image of another subcarrier, the radio system of the present invention permits highly integrated low-IF transceiver implementation. In an exemplary embodiment, a multi-carrier transceiver includes an integrated receiver comprising a first mixer for mixing an input signal with a local oscillator signal to produce an in-phase downconverted signal. Additionally, a first phase shifter phase-shifts the local oscillator signal to produce a quadrature local oscillator signal, and a second mixer mixes the input signal with the quadrature local oscillator signal to produce a quadrature downconverted signal. Thereafter, a second phase shifter phase-shifts, or rotates, the quadrature downconverted signal to produce a rotated quadrature downconverted signal.

Abstract: Methods and systems for allocating control channels in a radiocommunication system are disclosed. Control channels are associated with dedicated traffic channels. The allocation history of dedicated traffic channels can be monitored to determine which dedicated traffic channels are allocated most frequently to a base station. A control channel can then be allocated to the base station based on the allocation history of the associated dedicated traffic channels.

Abstract: A first wireless unit engages in contemporaneous participation in a plurality of wireless networks. A connection is established with a second wireless unit in a first wireless network. Then, a hold time-out period is determined, and the first wireless unit enters a hold mode with respect to the first wireless network. While in hold mode, the first wireless unit establishes a connection with a third wireless unit in a second wireless network. This may include the first wireless unit paging the third wireless unit and acting as a master unit in the second wireless network. Alternatively, the first wireless unit may periodically listen for paging messages from a master unit, and respond when paged, thereby becoming a slave in the second wireless network. The first wireless unit then participates in activities in the second wireless network. Upon expiration of the hold time-out period, the first wireless unit resumes active participation in the first wireless network.

Abstract: The invention relates to synchronizing in communication systems by using a sequential correlation technique. A digital sequence known to the receiver, a so-called signature, is allocated a plurality of segments. The segments are correlated, segment for segment, in a correlator (300) which is equally as long as the segment. The segments may have the same or different bit patterns. When a first segment is received in the correlator (300) and the correlation value of this segment exceeds an associated threshold value, the segment is accepted as received and is saved in a memory (308) in response to a signal from the control unit (311). A timer (319) is set to a time point that corresponds to the length of the segments. There is then correlated a second segment whose correlation value on the signal from the timer (319) is added (304) to the value stored in the memory (308). If the sum exceeds an associated threshold value, the sum is stored in the memory (308). Detection continues in this way.

Abstract: The air interface of a private radio system is adapted to be compatible with the air interface of a cellular mobile network. The private radio system's beacon channel includes a dual-burst type of frequency correction channel and synchronization channel. The burst formats of these two channels are defined according to the frequency correction channel and synchronization channel burst formats used in the cellular mobile network. An information message carried in the private synchronization channel includes status and identity information related to the private radio system. An access request channel is defined for the private radio system, which enables a mobile terminal to request access to the private radio system. The protocol of the private radio system's access request channel (in the uplink) is similar to the protocol of the cellular network's access grant channel used in the downlink.

Abstract: Radio beacon transmission between a private radio communications base station and a mobile terminal within the transmission range of the private radio communications base station designed to prevent interference with overlapping uncoordinated private radio communications networks is provided by jittered beacon transmission. The private base station transmits radio beacon bursts at jittered time intervals, which vary pseudo-randomly to prevent repeated radio beacon collisions between uncoordinated private radio communications networks with overlapping transmission ranges. The beacon time jittering is performed pseudo-randomly in a pattern which is associated with a base station identification value. The mobile terminal derives the base station associated identification value and status information from a received radio beacon and determines if the base station is available for communications with the mobile terminal.