Abstract: A method and apparatus is provided for allowing communication of a secondary communication device over spectrum allocated to a primary user. During operation a node wishing to communicate will determine a route to a destination device that will cause a least amount of interference to a primary communication system. Communication will then take place only if the sum of all communications along the route will not cause interference to the primary communication system.

Abstract: A method and apparatus for a highpass filter structure using transmission line construction which has multiple output tabs for selection of corner frequencies utilizing a plurality of resonators coupled to the transmission line. The transmission line has a characteristic impedance which increases exponentially with respect to a distance from the input.

Abstract: A method and apparatus is provided for allowing communication of a secondary communication device (105) over non-licensed spectrum. During operation a replica transmission (114) will be periodically transmitted by a base station (111) within the secondary communication system (121). This test signal is used to exercise the beacon detection apparatus (305) of transceivers utilizing the secondary communication system. If the detection fails, transmission by the transceiver is prohibited.

Abstract: A direct sequence spread spectrum (DSSS) receiver (100) consistent with certain embodiments has a frequency generator (112) that generates a local oscillator signal without use of a piezoelectric crystal. A frequency converter (108) receives the local oscillator signal and mixes the local oscillator signal with a received DSSS signal to produce a down-converted signal. The received DSSS signal is encoded using a first set of DSSS code. A differential chip detector (116) receives the down-converted signal and converts the down-converted signal to a differentially detected signal. A correlator (120) receives the differentially detected signal and correlates the detected signal with a set of DSSS codes that are time-shifted from the first set of DSSS codes. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A process for merging and using the Mediation Device Protocol with a network layer protocol. Under the merged protocol, each device joining a network enters into two stages: the Set-Up Stage and the Normal Operational Stage. During the Set-Up Stage, the device identifies its neighbors, builds a neighborhood list, obtains a Logical ID, and picks a parent node in the network. After the Set-Up Stage is complete, the device enters the Normal Operational Stage where it will send/receive control and data messages, invite and help new nodes to join the network, recover from broken links or topology changes, and other normal network operations.

Abstract: A cluster tree network formed by self-organization of a number of nodes. The method of self-organization includes processes for cluster formation, cluster network maintenance, intra-cluster communication. In the cluster formation process, each node discovers if any neighboring node is a cluster head or if any node is already a member of a cluster (thus making it a networked node), and if a cluster head or a networked node is discovered, each node establishes a communication link with the cluster head or the networked node. If no cluster head or networked node is discovered, the node itself becomes a cluster head. The network is maintained by each node periodically broadcasting a HELLO message to neighboring nodes, receiving responses to the HELLO message and updating a neighbor list in accordance with responses to the HELLO message. Multi-cluster networks are also provided using the processes of inter-cluster network formation, inter-cluster network maintenance, and inter-cluster communication.

Abstract: A method and apparatus for reducing power consumption within a wireless receiver is provided herein. Particularly, the use of partial chip sequence correlation to reduce the average power consumption of a direct sequence spread spectrum (DSSS) wireless transceiver is provided herein. During operation, the receiver will attempt to correlate, or de-spread, less than all chips that constitute a symbol. A partial correlation may be performed on M chips, where M may be much less than N, the number of chips that represent a whole symbol. In a preferred embodiment, the M chips are the first M chips in the symbol.

Abstract: A signaling system is provided in which a spread spectrum code is cyclically shifted by a cyclical shift dictated by a bit pattern of one or more bits. The cyclically shifted spread spectrum code is used to modulate a carrier frequency, and transmitted from a transmitter to a receiver. At the receiver the signal including the cyclically shifted spectrum code is demodulated to recover the cyclically shifted code. The cyclical shift is then determined and the bit pattern which is associated with the cyclical shift is output. The method can be used in direct sequence spread spectrum communication.

Abstract: An “identical beacons” field (401) is inserted near the beginning of a transmitted beacon (403) that contains either an integer equal to the number of consecutive identical beacons sent (i.e., identical to the one presently being transmitted) or a repetition bit indicating whether or not the beacon contains changed information when compared to a prior-sent beacon. After sleeping awhile, a node (302-304) wakes up, receives a first portion of the beacon containing the identical beacons field, and analyzes the identical beacons field. Based on the analysis, the node makes a decision on whether to remain “awake” for reception of the remaining beacon or to return to sleep.

Abstract: An “identical beacons” field (401) is inserted near the beginning of a transmitted beacon (403) that contains either an integer equal to the number of consecutive identical beacons sent (i.e., identical to the one presently being transmitted) or a repetition bit indicating whether or not the beacon contains changed information when compared to a prior-sent beacon. After sleeping awhile, a node (302-304) wakes up, receives a first portion of the beacon containing the identical beacons field, and analyzes the identical beacons field. Based on the analysis, the node makes a decision on whether to remain “awake” for reception of the remaining beacon or to return to sleep.

Abstract: A low power consumption protocol for low power communication devices attached to an asynchronous network is described. In this protocol, a communication device is used as a high communication duty cycle Mediation Device (MD), thus permitting other communication devices to use a low communication duty cycle framing structure. The MD functions as a storage and retrieval service for messages between two devices when one device is not able to communicate. When the previously unavailable device becomes available, it can check in with the MD to retrieve any missed messages and respond to these messages accordingly. In a communication network, each of the low power communication devices can be configured to behave as MD's for a small amount of time. Sharing this responsibility among all communication devices in the network allows each device to maintain an low average communication duty cycle. This technique is applicable to a low power, low cost, zero-configuring, self-organizing, asynchronous network.

Abstract: A technique for intra-piconet location determination and tomography is described. This technique uses received signal strength indicator (RSSI) values in conjunction with transmitted power levels to determine the relative location of each device within a small network employing frequency hopped spread spectrum transmission. In addition to the location determination properties of the invention, the geometry of the devices in the network, as well as the path loss information between pairs of devices, may be used to infer the location of absorbers and reflectors within the piconet. This absorption and reflection information may be used in creating the piconet tomography. The approach described in this specification may be applied in conjunction with the Bluetooth wireless Personal Area Network (PAN) specification to determine device locations, mitigate the effects of multi-path, and perform indoor location and security functions, and other application functions requiring cost-effective location determination.

Abstract: A cluster tree network formed by self-organization of a number of nodes. The method of self-organization includes processes for cluster formation, cluster network maintenance, intra-cluster communication. In the cluster formation process, each node discovers if any neighboring node is a cluster head or if any node is already a member of a cluster (thus making it a networked node), and if a cluster head or a networked node is discovered, each node establishes a communication link with the cluster head or the networked node. If no cluster head or networked node is discovered, the node itself becomes a cluster head. The network is maintained by each node periodically broadcasting a HELLO message to neighboring nodes, receiving responses to the HELLO message and updating a neighbor list in accordance with responses to the HELLO message. Multi-cluster networks are also provided using the processes of inter-cluster network formation, inter-cluster network maintenance, and inter-cluster communication.

Abstract: Location related information is collected for a network of communication devices that each is operable in a coordinating mode and in a non-coordinating mode. While in the coordinating mode, each communication device collects and stores location determining information (410, 420). Using the location determining information collected by one or more of the communication devices over multiple instances of operation in the coordinating mode, location information is calculated or updated for selected devices within the network (510, 520, 530, 540). In one embodiment, each device operates to mediate communication activities among others devices of the network while in the coordinating mode.

Abstract: A method and apparatus for encoding and decoding signals using code position modulation (CPM) in a communication system. The encoding method includes storing an N-chip pseudo-random noise sequence, such as an m-sequence, in a circular shift register and circularly shifting it to obtain a shifted m-sequence. The shifted m-sequence is compared to an m-bit symbol corresponding to the k bit information value. If the shifted m-sequence and the m-symbol match, the shifted m-sequence is output as the N-chip CPM sequence. Alternatively, the m-symbol is used as an initial condition for a pseudo-noise sequence generator. The corresponding decoder stores an N-chip m-sequence in a circular shift register and a correlates shifted version of the m-sequence with a received N-chip CPM sequence. When a peak in the correlation value is detected, an m-bit field is retrieved from the circular shift register and mapped back to a k-bit information value.

Abstract: Location related information is collected for a network of communication devices that each is operable in a coordinating mode and in a non-coordinating mode. While in the coordinating mode, each communication device collects and stores location determining information (410, 420). Using the location determining information collected by one or more of the communication devices over multiple instances of operation in the coordinating mode, location information is calculated or updated for selected devices within the network (510, 520, 530, 540). In one embodiment, each device operates to mediate communication activities among others devices of the network while in the coordinating mode.

Abstract: A transceiver device (52 or 10) operates as a source of a data transmission in a communication system (50) capable of dynamically allocating spectrum for transmission of the data transmission between the transceiver device (52) and a second transceiver device (51). The transceiver device (10) includes a transmitter, a receiver coupled to the transmitter and a processor or controller (12) coupled to the transmitter and receiver. The transceiver device is programmed to monitor the spectrum (channels 1-13 of FIG. 3) to determine if a portion (channels 4-8 for example in time slot 8) of the spectrum is available. The transceiver determines what portion of the spectrum is desired for data transmission and then transmits (see time slots 11 and 13) the data transmission within a dynamically selected portion of the available spectrum.

Abstract: A method and apparatus for encoding and decoding signals using code position modulation (CPM) in a communication system. The encoding method includes storing an N-chip pseudo-random noise sequence, such as an m-sequence, in a circular shift register and circularly shifting it to obtain a shifted m-sequence. The shifted m-sequence is compared to an m-bit symbol corresponding to the k bit information value. If the shifted m-sequence and the m-symbol match, the shifted m-sequence is output as the N-chip CPM sequence. Alternatively, the m-symbol is used as an initial condition for a pseudo-noise sequence generator. The corresponding decoder stores an N-chip m-sequence in a circular shift register and a correlates shifted version of the m-sequence with a received N-chip CPM sequence. When a peak in the correlation value is detected, an m-bit field is retrieved from the circular shift register and mapped back to a k-bit information value.

Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates such as large silicon wafers by forming a compliant substrate for growing the monocrystalline layers. An accommodating buffer layer comprises a layer of monocrystalline oxide spaced apart from a silicon wafer by an amorphous interface layer of silicon oxide. The amorphous interface layer dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. The accommodating buffer layer is lattice matched to both the underlying silicon wafer and the overlying monocrystalline material layer. Any lattice mismatch between the accommodating buffer layer and the underlying silicon substrate is taken care of by the amorphous interface layer. In addition, formation of a compliant substrate may include utilizing surfactant enhanced epitaxy, epitaxial growth of single crystal silicon onto single crystal oxide, and epitaxial growth of Zintl phase materials.

Abstract: Reference circuits are provided that include circuit components formed from both a composite semiconductor and silicon on a single integrated circuit. The reference circuits provide a reference current that is a function of the threshold voltage of the compound semiconductor device. The reference circuits may include, for example, a HEMT formed on a gallium arsenide layer, which overlays at least a portion of a silicon substrate. A MOSFET formed on the silicon substrate is coupled to the HEMT through a current mirror so that both devices are coupled to receive current based on a common current. Each device is coupled to one input of an error amplifier that provides an output signal that adjusts the common current.