Abstract: Embodiments of the invention disclose a system and a method for determining a rank of a node in a multi-hop wireless network, wherein the network includes a gateway node, client nodes, and relay nodes, wherein a node p(i) is a default parent of the node i having a rank, and the network uses a directed acyclic graph (DAG) topology. The method comprises steps of transmitting at least one data packet from the node to the default parent node over a wireless link; counting a number of successful transmissions of most recent transmissions of data packets; determining an expected transmission time (ETX) for the wireless link based on the number of successful transmissions in the most recent transmissions; and assigning a rank R(i) to the node based on the rank of the parent node and the ETX.

Abstract: A system for exchanging energy wirelessly includes an array of at least three objects, wherein the objects have similar resonant frequencies, wherein each object is electromagnetic (EM) and non-radiative and generates an EM near-field in response to receiving the energy. Each object is electrically isolated from the other objects and arranged at a distance from all other objects, such that upon receiving the energy, the object is strongly coupled to at least one other object via a resonant coupling of evanescent waves. An energy driver provides the energy at the resonant frequency to at least one object in the array, such that, during an operation of the system, the energy is distributed from the at least one object to all other objects in the array via the resonant coupling of the evanescent waves.

Abstract: A method transmits an L bit packet in a relay network including a source node, a relay node and a destination node. The source node partitions the packet into first fragment of ?L bits and a second fragment of (1??) bits. The first fragment is transmitted from the source node to the relay node at a first data rate during a first phase. The second fragment is transmitted from the source node to the destination node at a second data rate during a second phase while the first fragment is retransmitted from the relay node to the destination node at a third data rate.

Abstract: Channel state information for closed-loop transmit precoding in MIMO networks is fed back from the MSs to the BSs. The feedback is quantized using codebooks shared by the MSs and BSs to reduce overhead. The codebooks can be full-rank or rank-one. The quantized feedback is applicable to any definitions of MIMO channel covariance matrix as well as MIMO channel matrix. Since these codebooks are designed for closed-loop MIMO precoded transmissions, no additional memory is needed to store the codebooks at the BS and the MS only for the quantized feedback purposes.

Abstract: Soft decision decoding of a codeword of a Reed-Muller (RM) code by selecting an optimal decomposition variable i using a likelihood calculation. A code RM(r, m) is expressed as {(u, uv)|u?RM(r, m?1) and v?RM(r?1, m?1)}, where uv denotes a component-wise multiplication of u and v, and (u, uv)=(r1, r2). A receive codeword is separated into r1=u and r2=uv based on the optimal decomposition variable, and r2 is decoded according to the optimal decomposition variable, using a RM(r?1, m?1) decoder to obtain a decoded v and a first set of decoded bits. The decoded v is combined with r1 using (r1+r2v)/2, and (r1+r2v)/2 is decoded using a RM(r, m?1) decoder to obtain a decoded u and a second set of decoded bits.

Abstract: Embodiments of the invention describe a method for antenna selection (AS) in a wireless communication network. The network includes a base station and a transceiver, wherein the transceiver has a set of antennas, and wherein the transceiver is configured to transmit a frequency-hopped sounding reference signal (SRS) from a subset of antennas at a time. The base station determines a type of a training transmission based on a number of the subbands and a number of subsets in the set of antennas, and transmits an instruction including the type to the transceiver.

Abstract: A dynamic voltage scaling system for a packet-based data communication transceiver includes a constant voltage supply, a variable voltage supply, and a voltage control unit. The constant voltage supply is configured to supply a constant voltage to at least one parameter-independent function of the transceiver, and the variable voltage supply is configured to supply a variable voltage in accordance with a control signal to at least one parameter-dependent function of the transceiver. Parameter-independent transceiver functions perform operations independent of a predetermined parameter and parameter-dependent transceiver functions perform operations dependent on the predetermined parameter The voltage control unit is configured to generate the control signal based on information provided by at least one parameter-independent transceiver function about the predetermined parameter.

Abstract: Embodiments of the invention describe a method for antenna selection (AS) in a wireless communication network, the network comprising user equipment (UE), wherein the UE comprises a plurality of subsets of antennas including a selected subset of antennas and an unselected subset of antennas, wherein only the selected subset of antennas is used for transmitting user data, and wherein the UE is configured to transmit only from a subset of antennas at a time. The method transmits the user data from the selected subset of antennas within a set of subframes, and transmits a sounding reference signal (SRS) from the unselected subset of antennas within at least one subframe in the set of subframes to enable antenna selection for user data transmission.

Abstract: Soft decision decoding of a codeword of a Reed-Muller (RM) code by selecting an optimal decomposition variable i using a likelihood calculation. A code RM(r, m) is expressed as {(u, uv)|u?RM(r, m?1) and v?RM(r?1, m?1)) where uv denotes a component-wise multiplication of u and v, and (u, uv)=(r1, r2). A receive codeword is separated into r1=u and r2=uv based on the optimal decomposition variable, and r2 is decoded according to the optimal decomposition variable, using a RM(r?1, m?1) decoder to obtain a decoded v and a first set of decoded bits. The decoded v is combined with r1 using (r1+r2v)/2, and (r1+r2V)/2 is decoded using a RM(r, m?1) decoder to obtain a decoded u and a second set of decoded bits.

Abstract: Embodiments of the invention describe a method for joint resource blocks assignment and antenna selection (AS) in a wireless communication network, the network comprising user equipment (UE), wherein the UE comprises a plurality of subsets of antennas, the UE is configured to transmit a sounding reference signal (SRS) from a subset of antennas at a time. The method transmits a first SRS from a first subset of antennas and a second SRS from a second subset of antennas. Upon receiving, in response to the transmitting of the first SRS and the second SRS, information related to an optimal subset of antennas, and information related to an optimal subset of resource blocks, the method transmits a data symbol from the optimal subset of antennas using the optimal resource block.

Abstract: A network includes a master and a set of slaves that communicate orthogonal frequency-division multiplexing (OFDM) and time division multiple access (TDMA) symbols on sub-carriers. A master broadcasts to the set of slaves using downlinks and all of the sub-carriers, a broadcast polling packet including data packets for each slave and sub-carrier assignments for the slaves. Each slave, in response to receiving the downlink polling packet, transmits simultaneously a response packet to the master using uplinks and the assigned sub-carriers. The master then transmits to the set of slave using the downlinks and all of the sub-carriers, a group acknowledgement packet, wherein the broadcast polling packet, the response packet, and the group acknowledgement packet comprise one superframe in one communication cycle, and wherein the broadcasting on the downlinks and the transmitting on the uplinks are disjoint in time.

Abstract: A network includes a master node (master) and a set of slave nodes (slaves). The network uses orthogonal frequency-division multiplexing (OFDM) and time division multiple access (TDMA) symbols on sub-carriers. During a first downlink transmission from the master to the set of slaves using downlinks and all of the sub-carriers, a broadcast polling packet including data packets for each slave and sub-carrier assignments for the slaves is broadcast. Each slave transmits simultaneously to the master using uplinks and the assigned sub-carriers, a first response packet after receiving the broadcast polling packet. The master then broadcasts using the downlinks and all of the sub-carriers, a group acknowledgement packet, wherein the broadcast polling packet, the response packet, and the group acknowledgement packet include one superframe in one communication cycle, and wherein the broadcasting on the downlinks and the transmitting on the uplinks are disjoint in time.

Abstract: A method estimates a wireless channel at a receiver. The signal is transmitted using narrowband orthogonal frequency division demultiplexing (OFDM) and frequency subcarriers, and the signal includes a set of data tones and a set of pilot tones. The channel and pilot tone interference are estimated based on all the pilot tones extracted from the signal and a channel model. The set of data are equalized based on the channel estimate. Data interference is detected according to the pilot interference and the equalized data tones. Subcarrier interference-to-noise ratios are determined based on the data interference. Signal strengths of the data tones are determined based on the equalized data tones, log-likelihood ratios of bits represented by the data tones are determined based on the subcarrier interference-to-noise ratios and the signal strength of the data tones.

Abstract: A network includes a transmitter and a receiver, wherein the transmitter includes a set of transmit antennas and the receiver includes a set of receive antennas. The transmitter duplicates a packet as copies of the packet, and selects subsets of the set of transmit antennas independent of channel characteristics between the subsets of transmit antennas and the set of receive antennas, wherein combinations of the antennas in the subsets of the transmit antennas are different. The receiver selects subsets of the set of receive antennas independent of channel characteristics between the subsets of receive antennas and the set of transmit antennas, wherein combinations of the antennas in the subsets of the receive antennas are different. The selected subsets are used to transmit the packet, and retransmit the packet in case of a failure in a previous transmission.

Abstract: A hybrid communication network for a transportation safety system includes a wired network including a set of fixed nodes. Each fixed node includes a wired interface for connecting the fixed node to the wired network and at least one wireless interface. The set of fixed nodes further includes a head node at a first end of the wired network connected to a controller, a terminal node at a second end of the wired network, and a set of relay nodes arranged between the head node and the terminal node. A wireless network includes a set of mobile nodes and a set of fixed nodes connected to the wired network. Each mobile node includes at least one of the wireless interfaces, and each mobile node is arranged in a moveable car.

Abstract: A hybrid communication network for a transportation safety system includes a fixed wired nodes and mobile wireless nodes. Because the wired nodes operate independently packets transmitted by the wired nodes to the wireless nodes need to be synchronized. A downlink travel time for downlink packets traveling from a controller to the wireless nodes is determined. Then, the controller schedules downlink data intervals (DDI) based on the downlink travel time; and transmits downlink packets to the wireless nodes during the DDI, such that a latency requirement of the transportation safety system is satisfied.

Abstract: In a network for a safety system in a transportation system, the transportation system includes a shaft and a car arranged in the shaft. A first wall node is at a first end of the shaft and a second wall node is at a second end of the shaft to communicate safety messages with the car. Each wall node includes at least one wireless transceiver connected to one or more antennas. Each car in the shaft includes at least two wireless transceiver connected to one or more antennas, wherein the first transceiver of the car uses a first frequency and the second transceiver of the car uses a second frequency to communicate each safety messages in duplicate. A wired backbone connects the set of wall nodes to a controller of the safety system of the transportation system.

Abstract: A method transmits a sequence of symbols in a multiple-input multiple-output (MIMO) network including a transmitter having a set of transmit antennas and a receiver having a set of receive antennas. The sequence of symbols is represented by a vector S=[S1 S2 S3 S4]T of individual symbols, where T is a transpose operator. The individual symbols are transmitted as a transmit matrix S = [ S 1 - S 2 * S 1 - S 2 * S 2 S 1 * S 2 S 1 * S 3 - S 4 * - S 3 S 4 * S 4 S 3 * - S 4 - S 3 * ] , where * is a complex conjugate, and wherein each column of the matrix S represents the symbols transmitted at each transmission interval, and subscripts index the set of transmit antennas.

Abstract: A wireless sensor network includes an initial set of anchors at known locations, and a set of sensors at unknown locations. Ranges, from each sensor to at least three of the anchors, determine a position, an anchor ranging weight, and an anchor position weight. For each anchor, the anchor ranging weight and the anchor position weight form a combined weight. A weighted least square (WLS) function for the positions and the combined weights is minimized to determine a position of the sensor, and a sensor position weight. The sensor is identified as being a member of a set of candidate anchor nodes, and the candidate anchor node with a largest sensor position weight is selected to be transformed to another anchor to minimize propagation of errors in the positions of the set of sensors.

Abstract: A method allocates resources in an orthogonal frequency-division multiple access (OFDMA) network including a set of base stations (BSs), and a set of mobile stations (MSs) for each BS. Each cell includes a center and edge zone. A node weighted constraint graph is constructed for the network. Maximal independent sets in the graph are searched as sub-channels are allocated to the MSs in edge zones. Remaining bandwidth is allocated to the MSs in the center zones. Power is assigned to the sub-channels so that inter-cell interference is minimized and traffic load is maximized.