A system and method for transmitting data ultrasonically through biological tissue employs a network of a plurality of nodes, at least a portion of the nodes implantable within the biological tissue. At least one implanted node includes a transmitter having an orthogonal frequency division multiplex signal generator to encode an ultrasonic signal for transmission through the biological tissue to an ultrasonic receiver at another node.

Methods and systems for communication with an optimized constellation include coding an input data stream to a symbol stream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference. The symbol stream is modulated onto a transmission signal and subsequently demodulated at a receiver to produce a received symbol stream. The received symbol stream is decoded to a bitstream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference.

A method for performing link adaptation includes in a first network node of a wireless network: initializing data transmission with a second network node of the wireless network by transmitting a request-to-send message to the second network node and by receiving a clear-to-send message from the second network node, wherein the request-to-send message and the clear-to-send message are transmitted on one or more channels of the wireless network; after said initializing, generating a first data packet of the data transmission, wherein said generating comprises processing the first data packet with link adaptation parameters fixedly associated for use in connection with first data packets of data transmissions, wherein said link adaptation parameters are included in a subset of most robust link adaptation parameters supported by the first network node; receiving, from the second network node, a message indicating new link adaptation parameters for use in a subsequent data transmission; and generating a second data packet of the data transmission, wherein said generating the second data packet comprises processing the second data packet with the new link adaptation parameters indicated in the message.

Provided are a data transmitting or receiving method and device for dual Transport Blocks (TBs), a transmitter and a receiver. Data to be transmitted is divided into two portions, where transport blocks TB1 and TB2 are generated respectively according to a corresponding predetermined Modulation Coding Scheme (MCS) for each portion. The TB1 is modulated into an amplitude weighted complex symbol sequence S1, and the TB2 is modulated into an amplitude weighted complex symbol sequence S2. The S1 and the S2 are superposed to generate a complex symbol sequence S3 corresponding to a new TB, where the complex symbol sequence S3 corresponding to the new TB possesses Gray properties. The new TB is transmitted to a receiver.

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the code rate, a non-uniform constellation from one or several groups of constellations each comprising one or more constellations.

Techniques are presented for mapping a digital data sequence into a signal point sequence for transmission. The signal point sequence belongs to a set of possible signal point sequences. In one example, a digital data sequence is received. Forbidden branch flags that forbid certain signal points in the possible signal points sequences are applied. The signal point sequence is selected from a subset of all the possible signal point sequences based on the digital data sequence. The subset is defined by the forbidden branch flags.

Embodiments of communications devices and methods for operating a communications device are described. In an embodiment, a communications device includes a complex multiplier configured to multiply a first input complex signal with a second input complex signal to generate an output complex signal, an amplifier configured to amplify an imaginary part of the output complex signal to generate an amplification result, a delay element configured to delay a rotation angle signal that is related to the second input complex signal, and a subtractor configured to subtract the amplification result from the delayed rotation angle signal to generate the rotation angle signal. Other embodiments are also described.

The present invention relates to a satellite communications system comprising a satellite with a spatial digital modulator for transmitting an incoming bit stream in multiple beams, wherein the spatial digital modulator configured to generate transmit symbols by dividing the incoming bit stream into symbols of a symbol alphabet and to allocate each transmit symbol to a specific beam. The invention further relates to a method for transmitting a bit stream by such a satellite communications system.

A technique for radio transmitting data is described. As to a method aspect of the technique data to be transmitted to a receiver is represented by at least two partial modulation symbols. Each of the at least two partial modulation symbols is associated to a different layer of the radio transmission to the receiver. A modulation symbol is generated by combining the at least two partial modulation symbols at different power levels according to the associated layer. The modulation symbol is transmitted to the receiver.