Abstract: Described are methods and devices for identifying a group that include various methods to determine a group. Also described are devices and methods for attempting communication with a missing member of the group include different manners in which to determine information related to an entry of a group. The described devices and methods may be particularly beneficial at the particular time the certain group members plan to be or are in communication with one another. In this way, in the event that two or more entries of a group planned to be in communication or are in communication in-real time, in accordance with the disclosed devices and methods, the parties may be able to bring one or more other entries of the group into the communication as needed or desired.

Abstract: Disclosed are devices and methods of communication devices that are configured to be a part of clustered displays. A communication device may be a mobile communication device. Such a device may include a cluster module configured to determine that the device is a license owning unit, a content module configured to receive data including content via a transceiver when it is determined that the device is a license owning unit and a distribution module configured to transmit output data via a transceiver, the output data being at least one portion of the data. The license owning unit is determined based on the reception characteristics of the devices of the cluster. The distribution by the license owning unit to other devices in the cluster is at the lowest resolution of any of the devices of the cluster.

Abstract: Described are methods and devices for identifying a group that include various methods to determine a group. Also described are devices and methods for attempting communication with a missing member of the group include different manners in which to determine information related to an entry of a group. The described devices and methods may be particularly beneficial at the particular time the certain group members plan to be or are in communication with one another. In this way, in the event that two or more entries of a group planned to be in communication or are in communication in-real time, in accordance with the disclosed devices and methods, the parties may be able to bring one or more other entries of the group into the communication as needed or desired.

Abstract: A method and apparatus for determining the relative locations of nodes in a wireless network is disclosed. A list of neighboring nodes of a master node of the wireless network is generated and, from this list, a list of independent nodes is generated. An adjacency table for the independent nodes is then generated by examining the neighbors of dependent nodes. Two independent nodes are determined to be adjacent nodes only if they are the only neighboring nodes of a dependent node. Relative locations of nodes in wireless network may be determined from the adjacency table.

Abstract: An adaptive channel access scheme allows for statistics that are collected to be used to group radio users into subgroups according to the desired statistic. The subgroups then utilize channels, separated by time or frequency, to access the communication system (100). The sub-grouping of the radio users is designed to help minimize the chances of channel-access collisions from occurring.

Abstract: A communication device (300) operates in a training mode to develop parameters based on estimates related to at least two different instances of channel conditions, such as indicated by bit error rates for channel transmissions (610, 620, 710, 720). The parameters are used to define a function that characterizes an optimized throughput or energy consumption per bit through varying channel conditions. The function is preferably of the form a0+a1*Log(1+Lp), where a0 and a1 are fitted parameters, and Lp the frame size. The device responds to changes in channel conditions by transmitting messages on the communication channel using a frame size adapted for channel conditions based on the particular function and the developed parameters (640–680, 740–780).

Abstract: A communication system provides for data collection and route discovery for a network of distributed nodes. A base code having a data collection function occasionally sends agent packets to selected nodes of the network (620), and these nodes in turn route the agent packets to other nodes. A route suitability level is maintained for each node that reflects the suitability of that node for routing packets to the base node (5 10). At least some data packets contain reporting criteria for particular nodes (620). When a condition exists at a node that meets the reporting criteria, a selected packet is updated with reporting data, and routed toward the based node via a neighbor node based on the route suitability level of the neighbor node (550,552,555).

Abstract: A system and method for inferring an electronic rendering (170) of an environment (110) comprises a plurality of devices (341 and 345), and a processing device. Each wireless device is capable of determining a distance between a neighboring wireless device. Moreover, each device is capable of performing at least one of the following: determining an environmental attribute of the environment, and determining a location of an object in the environment. The processing device gathers information determined from the plurality of devices and infers the electronic rendering of the environment based on the information gathered.

Abstract: A method and apparatus for direct sequence spread spectrum communication having low complexity. In the transmitter, the data bit is spreaded by a code sequence, a reference code is interleaved with the code sequence, and together they are transmitted by the transmitter. The corresponding receiver recovers the data signal from the received signal by transforming the received signal to a complex base band signal and differentially decoding the base band signal at the chip level. The spreaded signal is despreaded by the chip-level differential operation, thus eliminating the decorrelation operation, and so significantly reducing the cost of the overall system. Furthermore, this system is very robust to any carrier frequency drift since the chip-level differential operation is used, thus releasing the reference clock or crystal requirements, and so further reducing the cost of the system.

Abstract: A network protocol for low-cost, low-power devices coupled to a self-organizing wireless network using a spanning tree backbone architecture is described. In this protocol, physical and logical network construction and maintenance operations, which supports efficient data routing in the network, are performed. The construction phase in conjunction with the maintenance phase insures the self-organizing capability of the network. At the same time, the maintenance operations provide a self-healing mechanism so that the network can recover from node failures and a self-updating mechanism so that the network can expand as more nodes enter the system. Also, the logical backbone hierarchy will facilitate multi-hop communication. The construction of a logical layered spanning tree backbone architecture from an underlying physical topology allows seamless data communication routing between all nodes in the network.

Abstract: According to the present invention a received Direct Sequence Code Division Multi-Access (DS-CDMA) signal is differentially decoded at the chip level. A number of signaling schemes can be used in the invention including (1) an ON/OFF signaling scheme in which a pseudo noise number (PN) code is sent only in response to one data bit value, and no signal is sent in response to the other bit value; (2) a Two Code signaling scheme in which bit values of 1 triggers a first PN code to transmitted, and a bit value of 0 triggers a second PN code to be transmitted; and (3) an M-ary signaling method in which a plurality of data bit patterns respectively, trigger a plurality of PN codes to be transmitted. After differential decoding the received signal is despread using one or more PN codes, that can be vector sums of two or more PN codes.

Abstract: An optically based location system and method of determining a location at a structure include a lighting infrastructure having lights at a structure. Each light is configured to illuminate and to transmit a respective relative or absolute terrestrial position through modulation of emitted light. An optical receiver is configured to detect the lights, to demodulate the position of detected lights, and to determine from the detection a position of the receiver. The receiver can have a conventional optical detector for determining a two-dimensional position of the receiver relative to a detected light, or can have a three-dimensional spot collimating lens and charged couple device optical detector for determining a three-dimensional position of the receiver relative to a detected light. The receiver and lights can be synchronized for converting a delay time into a distance measurement to calculate a distance between a light and the receiver.

Abstract: A beacon assisted asynchronous method of wireless communication according to the present invention enables initiating and target devices (12, 14) to remain in sleep mode most of the time and to periodically wake up to asynchronously, and directly, communicate with one another. Specifically, each of the initiating and target devices (12, 14) transmits a beacon while operating in a default transmit/receive mode (40, 40a, 42, 42a) and subsequently listens for a response. Alternatively, the initiating device (12) may enter a data packet message mode to receive a beacon from the target device (14) and to subsequently transmit a data packet message to the target device (14) after receiving the first beacon. The initiating device (12) minimizes the length of time in which it must wait to receive the target device beacon by timing a corresponding target beacon receive period based on stored data such as information based on previous communication with the target device (14).

Abstract: A network protocol for low-cost, low-power devices coupled to a self-organizing wireless network using a spanning tree backbone architecture is described. In this protocol, physical and logical network construction and maintenance operations, which supports efficient data routing in the network, are performed. The construction phase in conjunction with the maintenance phase insures the self-organizing capability of the network. At the same time, the maintenance operations provide a self-healing mechanism so that the network can recover from node failures and a self-updating mechanism so that the network can expand as more nodes enter the system. Also, the logical backbone hierarchy will facilitate multi-hop communication. The construction of a logical layered spanning tree backbone architecture from an underlying physical topology allows seamless data communication routing between all nodes in the network.

Abstract: A communication device (300) operates in a training mode to develop parameters based on estimates related to at least two different instances of channel conditions, such as indicated by bit error rates for channel transmissions (610, 620, 710, 720). The parameters are used to define a function that characterizes an optimized throughput or energy consumption per bit through varying channel conditions. The function is preferably of the form a0+a1*Log(1+Lp), where a0 and a1 are fitted parameters, and Lp the frame size. The device responds to changes in channel conditions by transmitting messages on the communication channel using a frame size adapted for channel conditions based on the particular function and the developed parameters (640-680, 740-780).

Abstract: A system and method for inferring an electronic rendering of an environment comprises a plurality of devices (224-228, 312-316, 320-328), and a processing device (232). Each wireless device is capable of determining a distance between a neighboring wireless device. Moreover, each device is capable of performing at least one of the following: determining an environmental attribute of the environment, and determining a location of an object in the environment. The processing device (232) gathers information determined from the plurality of devices and infers the electronic rendering of the environment based on the information gathered.

Abstract: A set of characteristics of an environment is inferred by obtaining at least a first location estimate of a first device at a first time and a second location estimate of the first device at a second time. A first path traveled (240) by the first device is established based on at least the first location estimate of the first device at the first time and the second location estimate of the first device at the second time. At least one characteristic of the environment is inferred based on the first path traveled by the first device.

Abstract: A communication system provides for data collection and route discovery for a network of distributed nodes. A base code having a data collection function occasionally sends agent packets to selected nodes of the network (620), and these nodes in turn route the agent packets to other nodes. A route suitability level is maintained for each node that reflects the suitability of that node for routing packets to the base node (510). At least some data packets contain reporting criteria for particular nodes (620). When a condition exists at a node that meets the reporting criteria, a selected packet is updated with reporting data, and routed toward the based node via a neighbor node based on the route suitability level of the neighbor node (550, 552, 555). The node also routes selected received packets that are destined for the base node to one or more neighbor nodes based on their route suitability level (540 542 545).

Abstract: A method and apparatus for direct sequence spread spectrum communication having low complexity. In the transmitter, the data bit is spreaded by a code sequence, a reference code is interleaved with the code sequence, and together they are transmitted by the transmitter. The corresponding receiver recovers the data signal from the received signal by transforming the received signal to a complex base band signal and differentially decoding the base band signal at the chip level. The spreaded signal is despreaded by the chip-level differential operation, thus eliminating the decorrelation operation, and so significantly reducing the cost of the overall system. Furthermore, this system is very robust to any carrier frequency drift since the chip-level differential operation is used, thus releasing the reference clock or crystal requirements, and so further reducing the cost of the system.

Abstract: A contention resolution method includes the steps of determining a contention has occurred and requesting contention resolution from radios in the system (604). Radios in the system receive the request and do not transmit in the next control frame (606). Group leader radios (202, 208 and 214) transmit the identification code they were able to demodulate in the previous frame to the master radio (608). The master radio (212) receives the information from the group leaders and transmits a control-channel access message to one of the contending radios (610).