Abstract: Communication devices, such as base nodes and modems, that comply with two or more different standards operate on a shared communication channel. To avoid mutual interference, a base node operating under a first standard reserves time using a contention free period designation. The base node allows devices operating under a second standard to communicate during the reserved time by not assigning the contention free period to another device operating under the first standard. Alternatively, a device using the first standard may avoid interference from transmissions generated under the second standard by modifying data packets prior to transmission. A prefix corresponding to a preamble in the second standard is added to the beginning of the data packet created under the first standard. Devices operating under the second standard observe the prefix and recognize that the channel is active. The second-standard devices backoff from transmission thereby minimizing interference.

Abstract: Systems and methods for building, transmitting, and receiving frame structures in power line communications (PLC) are described. Various techniques described herein provide a preamble design using one or more symbols based on a chirp signal that yields a low peak-to-average power ratio (PAPR). According to some techniques, the preamble may be constructed with one or more different types and/or number of symbols configured to identify a PLC domain operating in close physical proximity to another PLC domain. According to other techniques, one or more preamble symbols may be interspersed within a header portion of a PLC frame to facilitate estimation of a frame boundary and/or sampling frequency offset, for example, in the presence of impulsive noise. According to yet other techniques, a PLC detector may be capable of receiving and decoding two or more types of PLC frames (e.g., using different PLC standards).

Abstract: Systems and methods for building, transmitting, and receiving frame structures in power line communications (PLC) are described. Various techniques described herein provide a preamble design using one or more symbols based on a chirp signal that yields a low peak-to-average power ratio (PAPR). According to some techniques, the preamble may be constructed with one or more different types and/or number of symbols configured to identify a PLC domain operating in close physical proximity to another PLC domain. According to other techniques, one or more preamble symbols may be interspersed within a header portion of a PLC frame to facilitate estimation of a frame boundary and/or sampling frequency offset, for example, in the presence of impulsive noise. According to yet other techniques, a PLC detector may be capable of receiving and decoding two or more types of PLC frames (e.g., using different PLC standards).

Abstract: Various wireless precoding systems and methods are presented. In some embodiments, a wireless transmitter comprises an antenna precoding block, a transform block, and multiple transmit antennas. The antenna precoding block receives frequency coefficients from multiple data streams and distributes the frequency coefficients across multiple transmit signals in accordance with frequency-dependent matrices. The transform block transforms the precoded frequency coefficients into multiple time domain transmit signals to be transmitted by the multiple antennas. The frequency coefficients from multiple data streams may be partitioned into tone groups, and all the frequency coefficients from a given tone group may be redistributed in accordance with a single matrix for that tone group. In some implementations, the frequency coefficients within a tone group for a given data stream may also be precoded. In some alternative embodiments, tone group precoding may be employed in a single channel system.

Abstract: A wireless communication system. The system comprises transmitter circuitry (BST1), the transmitter circuitry comprising encoder circuitry (50) for transmitting a plurality of frames (FR). Each of the plurality of frames comprises a primary synchronization code (PCS) and a second synchronization code (SSC). The encoder circuitry comprises of circuitry (501) for providing the primary synchronization code in response to a first sequence (32). The encoder circuitry further comprises circuitry (502) for providing the secondary synchronization code in response to a second sequence (54) and a third sequence (56). The second sequence is selected from a plurality of sequences. Each of the plurality of sequences is orthogonal with respect to all other sequences. The third sequence is a subset of bits from the first sequence.

Abstract: Systems and methods for designing, using, and/or implementing slotted channel access techniques in network communications are described. In some embodiments, a method may include selecting one of a plurality of time slots within a contention access period (CAP), each of the plurality of time slots having a predetermined duration, and transmitting a packet during the selected time slot. For example, the time slot may be selected randomly or based on a round-robin algorithm. In some implementations, the duration of each of the plurality of time slots may correspond and/or be equal to: (a) a duration of a data packet of maximum size, (b) a sum of durations of a request-to-send packet, an interframe space, and a clear-to-send packet, and/or (c) a duration of a guaranteed time slot (GTS) or contention free period (CFP) request packet, as prescribed by a given communication protocol or standard.

Abstract: A method of operating a transmitter (FIGS. 3A and 5A) is disclosed. The method includes receiving a sequence of data bits (DATA), wherein each data bit has a respective sequence number. A first data bit of the sequence is spread (508) with a first spreading code (504) determined by the sequence number (502) of the first data bit. A second data bit of the sequence is spread (508) with an inverse of the first spreading code (506) determined by the sequence number (502) of the second data bit. The first and second data bits are modulated (510) and transmitted (516) to a remote receiver.

Abstract: System and method for signaling control information in a multi-carrier communications system to transmit data. A preferred embodiment comprises demodulating a first carrier that is used for transmitting a control channel transmission, determining a second carrier that is used for transmitting a data channel transmission based upon the demodulated control channel transmission, and demodulating the second carrier to obtain the data channel transmission. Additionally, designs for multi-carrier receivers are provided.

Abstract: A convolutionally encoded frame to be decoded includes a first portion of bits having additional error protection and another portion without additional error protection. The decoding of the frame involves reverse Viterbi decoding or Viterbi decoding on a reversed bit sequence followed by applying a serial list Viterbi algorithm to the first portion. The result is that the list of probable sequences have unique sets of bits in the first portion.

Abstract: A coordinated multipoint transmitter is for use with a network MIMO super-cell and includes a coordination unit configured to provide joint link processing to coordinate a multipoint transmission corresponding to a set of transmission points. Additionally, the coordinated multipoint transmitter also includes a transmission unit configured to transmit the multipoint transmission using the set of transmission points. Additionally, a coordinated transmission receiver is for use with a network MIMO super-cell and includes a reception unit configured to receive a multipoint transmission corresponding to a set of transmission points. The coordinated transmission receiver also includes a processing unit configured to process the multipoint transmission from the set of transmission points.

Abstract: Systems and methods for adaptive modulation and coding with frame size adjustment are described. In various implementations, these systems and methods may be applicable to Power Line Communications (PLC). For example, a method may include identifying a temporal region of a cyclostationary noise over which a frame is to be sent across a PLC network, the cyclostationary noise having a plurality of temporal regions, each of the plurality of temporal regions having a distinct spectral shape. The method may also include applying a given one of a plurality of Modulation and Coding Schemes (MCSs) to the frame to produce a modulated frame, wherein the given one of the plurality of MCSs is selected based, least in part, upon the spectral shape corresponding to the identified temporal region. The method may further include transmitting the modulated frame across the PLC network, at least in part, over the identified temporal region.

Abstract: Systems and methods for channel estimation using pilot-based symbols are described. In various implementations, these systems and methods may be applicable to Orthogonal Frequency-Division Multiplexing (OFDM)-based communications, for example, as used in Power Line Communications (PLC) or the like. For instance, a method may include receiving a frame over a communication channel at communications device deployed in an OFDM communications network, the frame including a frame control header, a channel estimation portion immediately following the frame control header, and a data payload immediately following the channel estimation portion, where the channel estimation portion includes at least one pilot symbol preceded by at least one of: a guard interval or a cyclic prefix. The method may also include performing a channel estimation operation for the communication channel based, at least in part, upon the channel estimation portion.

Abstract: Systems and methods for enhanced carrier sense multiple access (CSMA) protocols are described. In various implementations, these systems and methods may be applicable to Power Line Communications (PLC). For example, a method may include attempting to access a communications channel to transmit a frame after a backoff time proportional to a randomly generated number within a contention window (CW), the CW having an initial value carried over from a previous transmission of a different frame. Additionally or alternatively, some of techniques described herein may facilitate the spreading of the time over which devices attempt to transmit packets, thereby reducing the probability of collisions using, for example, Additive Decrease Multiplicative Increase (ADMI) mechanisms.

Abstract: Systems and methods for Carrier Sense Multiple Access (CSMA) and collision detection using a noise model are described. In various implementations, these systems and methods may be applicable to Power Line Communications (PLC). For example, a method may include receiving a signal via a communications channel in a PLC network, determining a feature of the signal, comparing the feature of the signal with a corresponding feature of a cyclostationary noise model, and taking a predetermined action based, at least in part, upon the comparison. In some implementations, taking the predetermined action may include determining whether to backoff or to transmit a packet over the communications channel. In other implementations, taking the predetermined action may include determining whether an error is due to a packet collision or due to a low quality of the communications channel.

Abstract: System and method for providing multiple access in a multi-band, orthogonal frequency division multiplexed (multi-band-OFDM) communications system. A preferred embodiment comprises determining a transmission bandwidth to support a performance requirement and configuring transmission bands in the multi-band-OFDM communications system based upon the transmission bandwidth, wherein the transmission bands may be made up of smaller transmission bands bonded together. Further comprising initializing communications with the configured transmission bands. The use of bonded transmission bands can provide increased data rates and/or increased range performance.

Abstract: A system comprises a base station, a plurality of mobile stations, and a packet scheduling algorithm that operates on the base station. The packet scheduling algorithm groups the plurality of mobile stations into a plurality of groups based on average throughput with the base station. The packet scheduling algorithm selects one of the plurality of groups for applying a scheduling metric.

Abstract: A method of Multi-Tone Mask (MTM) mode communications in a PLC network including a first router associated with a plurality of nodes. A super-frame spanning a time period is received within the subnetwork. The super-frame includes beacon frames in beacon slots within a beacon period, with each beacon frame in one of N TMs, a contention access period (CAP) including a plurality of CAP slots provided for each TM, and a poll-based contention-free period (CFP). The beacon frames provide time assignments within the super-frame including time assignments for the CAP slots and for the CFP, and TM assignments for the TMs in the CAP slots. One of nodes, another router in the subnetwork, or a router in another subnetwork transmits a broadcast frame on the PLC channel. The first router forwards the broadcast frame on the PLC channel in each of the N TMs within the time period.

Abstract: A wireless receiver (74) for receiving signals from a transmitter (72). The transmitter comprises a plurality of transmit antennas (TAT1?, TAT2?) for transmitting the signals, which comprise respective independent streams of symbols. Additionally, interference occurs between the respective streams. The receiver comprises a plurality of receive antennas (RAT1?, RAT2?) for receiving the signals as influenced by a channel effect between the receiver and the transmitter. The receiver also comprises circuitry (80) for multiplying the signals times a conjugate transpose of an estimate of the channel effect and times a conjugate transpose of a linear basis transformation matrix. The receiver also comprises circuitry (84) for selecting the linear basis transformation matrix from a finite set of linear basis transformation matrices. Lastly, the receiver comprises circuitry (88) for removing the interference between the respective streams.

Abstract: A method of powerline communications (PLC) over a PLC channel including a first node and at least a second node utilizes an algorithm that compiles frames having extended duration physical layer (PHY) headers. A duration or estimated duration of a null of the PLC channel is provided. An extended duration PHY header is compiled including a plurality of symbols and bits having a time duration of the PHY header of at least fifty percent (50%) more than the duration or estimated duration of the null. The compiling includes symbol repetition of at least a portion of the plurality of symbols or bit repetition of at least a portion of the plurality of bits. The first node transmits a frame including a preamble and the extended duration PHY header over the PLC channel to at least the second node.

Abstract: A circuit is designed with a measurement circuit (432). The measurement circuit is coupled to receive a first input signal (903) from a first antenna (128) of a transmitter and coupled to receive a second input signal (913) from a second antenna (130) of the transmitter. Each of the first and second signals is transmitted at a first time. The measurement circuit produces an output signal corresponding to a magnitude of the first and second signals. A control circuit (430) is coupled to receive the output signal and a reference signal. The control circuit is arranged to produce a control signal at a second time in response to a comparison of the output signal and the reference signal.