6536results about "Transmission rate adaptation" patented technology

Channel state information (CSI) can be used by a communications system to precondition transmissions between transmitter units and receiver units. In one aspect of the invention, disjoint sub-channel sets are assigned to transmit antennas located at a transmitter unit. Pilot symbols are generated and transmitted on a subset of the disjoint sub-channels. Upon receipt of the transmitted pilot symbols, the receiver units determine the CSI for the disjoint sub-channels that carried pilot symbols. These CSI values are reported to the transmitter unit, which will use these CSI values to generate CSI estimates for the disjoint sub-channels that did not carry pilot symbols. The amount of information necessary to report CSI on the reverse link can be further minimized through compression techniques and resource allocation techniques.

Various techniques of simple modifications to TCP / IP protocol and other susceptible protocols and related network's switches / routers configurations, are presented for immediate ready implementations over external Internet of virtually congestion free guaranteed service capable network, without requiring use of existing QoS / MPLS techniques nor requiring any of the switches / routers softwares within the network to be modified or contribute to achieving the end-to-end performance results nor requiring provision of unlimited bandwidths at each and every inter-node links within the network.

In embodiments of the present invention improved capabilities are described for a mobile broadband routable internet (MBRI) providing for carrier-grade, networked, broadband, IP-routable communication among a plurality of mobile devices, where the mobile devices may represent a plurality of nodes that are linked together through a mobile ad-hoc network (MANET). Mobile devices may operate as peers in a peer-to-peer network, with full IP routing capabilities enabled within each mobile device, thereby allowing routing of IP-based traffic, including deployment of applications, to the mobile device without need for infrastructure conventionally required for mobile ad hoc networks, such as cellular telephony infrastructure. Full IP-routing to mobile devices may allow seamless integration to the fixed Internet, such as through fixed or mobile access points, such as for backhaul purposes. Thus, the MBRI may function as a standalone mobile Internet, without connection to the fixed Internet, or as an IP-routable extension of another network, whether it be the Internet, a local area network, a wide area network, a cellular network, a personal area network, or some other type of network that is capable of integration with an IP-based network.

A system and method for delivering increases speed, security, and intelligence to wireline and wireless systems. The present invention increases channel capacity by using a parallel or multi-channel structure in such wireless and wireline at the edge or the core of. This new architecture of the present invention uses parallel bitstreams in a flexible way and distributed switching / routing technique, is not only to avoid the potential bottlenet of centralized switches, but also to increase speed with intelligence that is seamlessly integrating into the Fiber Optic Backbone such as WDM and SONET of the MAN / WAN network with a Real-time guarantees, different types of traffic (such as Stringent synchronous, isochronous, and asynchronous data messages) with different demands, and privacy & security of multi access and integrated services environment.

An adaptable orthogonal frequency-division multiplexing system (OFDM) that uses a multiple input multiple output (MIMO) to having OFDM signals transmitted either in accordance with time diversity to reducing signal fading or in accordance with spatial diversity to increase the data rate. Sub-carriers are classified for spatial diversity transmission or for time diversity transmission based on the result of a comparison between threshold values and at least one of three criteria. The criteria includes a calculation of a smallest eigen value of a frequency channel response matrix and a smallest element of a diagonal of the matrix and a ratio of the largest and smallest eigen values of the matrix.

A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.

Techniques to transmit data on a number of transmission channels in a multi-channel communication system using multiple transmission schemes requiring less channel-state information (CSI). These schemes may include a partial-CSI transmission scheme that transmits a single data stream on each transmit antenna selected for use and a “beam-forming” transmission scheme that allocates all transmit power to a single transmission channel having the best performance. Each transmission scheme may provide good or near-optimum performance for a specific range of operating conditions (or operating SNRs). These multiple transmission schemes may then be combined in a piece-wise fashion to form a “multi-mode” transmission scheme that covers the full range of operating conditions supported by the MIMO system. The specific transmission scheme to be used for data transmission at any given moment would then be dependent on the specific operating condition experienced by the system at that moment.

In a closed-loop wireless communication system, a codebook-based feedback mechanism is provided to enable non-unitary precoding for multi-stream transmission, where in each stream is optimized with suitable transmission power allocation and AMC. The codebook-based feedback mechanism uses a precoding codebook having a power allocation matrix which is constrained to specify that beamforming always applies full power to a predetermined beam. With this constraint, a one-bit power allocation feedback index may be used to switch between beamforming and spatial multiplexing.

An adaptive compression mechanism that dynamically selects compression algorithms applied to network application traffic to improve performance. One implementation includes an arbitration scheme that reduces the impact on computing resources required to analyze different compression algorithms for different network applications. The adaptive compression functionality of the present invention can be integrated into network application traffic management or acceleration systems.

A method for processing a Channel State Information Reference Signal (CSI-RS) in a wireless communication system based on a multiple access scheme is provided. The CSI-RS transmission method defines a plurality of CSI-RS patterns, assigns the CSI-RS patterns to individual cells, uses the CSI-RSs alternately per Physical Resource Block (PRB) so as to utilize the transmission powers of all antenna ports for transmitting CSI-RSs, transmits Coordinated Multi Point (CoMP) CSI-RSs and non-CoMP CSI-RSs separately, and mutes specific resources in association with the CSI-RS pattern of adjacent cells.

MIMO transmission methods are applied to communicaiton systems in which a transmitter has more than one transmit antenna and a receiver has more than one receive antenna. Information to be transmitted is divided into a plurality of subsignals according to the number of used transmit antennas and each subsignal is processed separately before it is emitted by the respective transmit antenna. In the receiver the different receive signals are processed thus that subsignals are detected and decoded and the contribution of each detected and decoded subsignal is subtracted from the receive signals and whereby a feedback channel from receiver to transmitter is used to send control information to the transmitter depending on the receive situation. In order to optimize the usage of the MIMO channel the invention proposes the in the receiver the link quality of each subsignal is determined and information of each subsignal is transmitted to the receiver via the feedback channel and that in the transmitter properties of the subsignals are controlled by the link quality information.

The present invention provides an FM Orthogonal Frequency Division Multiplexing (OFDM) modulation process that enable high-speed data communications over any transmission media and networks. The process is implemented with a modem device modulator and demodulator that provides communication with several other modem devices along any communication media that uses an FM OFDM modulation technique, a physical transmission medium such as power lines, or wireless (air), or cable, or twisted pairs communication media.

The present invention provides systems and methods for improved data communication between communication terminals such as a base station and an unmanned aerial vehicle. In some instances, the systems and methods described herein provide robust transmission uplink data such as control data and wideband transmission of downlink data such as image data or other sensor data, while avoiding interference between the uplink data transmission and the downlink transmission.

Method for computing and transmitting channel quality information in a multi-carrier communications system. A preferred embodiment comprises receiving a transmission from a transmitter, wherein the transmission occurs over a plurality of carriers, measuring a channel condition for each carrier in a plurality of carriers, computing a channel quality indicator based upon the measured channel condition, and providing the channel quality indicator to the transmitter. The channel quality indicator can be used at the transmitter to schedule transmissions to various users in the multi-carrier communications system to maximize utilization of the carriers as well as overall network performance.

Techniques for multiplexing and transmitting multiple data streams are described. Transmission of the multiple data streams occurs in “super-frames”. Each super-frame has a predetermined time duration and is further divided into multiple (e.g., four) frames. Each data block for each data stream is outer encoded to generate a corresponding code block. Each code block is partitioned into multiple subblocks, and each data packet in each code block is inner encoded and modulated to generate modulation symbols for the packet. The multiple subblocks for each code block are transmitted in the multiple frames of the same super-frame, one subblock per frame. Each data stream is allocated a number of transmission units in each super-frame and is assigned specific transmission units to achieve efficient packing. A wireless device can select and receive individual data streams.

A wireless terminal and network terminal are provided for implementing a new uplink OFDM protocol. In the new protocol, the wireless terminal has a first transmit chain for generating and transmitting a low rate mode OFDM transmission in a first frequency band of the OFDM band; and a second transmit chain for generating and transmitting a burst-mode transmission in a second frequency band of the OFDM band, the first frequency band being distinct from the second frequency band. An access channel is provided which is overlaid over the low rate mode transmissions of other users.

A method and apparatus for controlling OFDMA cellular networks is described. In one embodiment, the method comprises receiving channel characteristics and noise-plus-interference information measured at spatially distributed subscribers and assigning traffic channels for an orthogonal frequency-division multiple-access (OFDMA) network.

The present invention relates to a wireless communication system, and more particularly, discloses a method and an apparatus for transmitting and receiving duplicate data in a multicarrier wireless communication system. According to one embodiment of the present invention, a method in which a transmitter, which supports carrier aggregation for performing communication using N (N≧2) component carriers, transmits duplicate data, comprises the steps of: generating, in a media access control (MAC) layer of the transmitter, N duplicate data using radio link control (RLC) protocol data units (PDUs) from an RLC layer, and simultaneously transmitting, to a receiver, the respective N duplicate data on the N component carriers through respective N hybrid automatic repeat and request (HARQ) entities.

The present invention provides a method for feedback and transmission of multi-user (MU) multiple input multiple output (MIMO) in a wireless communication system. The method includes steps of selecting subset codebook or full code book based on traffic load of a base station, and broadcasting the selected codebook to user equipments. In high traffic load, subset codebook is selected, and in low traffic load, full codebook is selected. User stations calculated a channel quality indicator of a spatial codeword vector that is included in the selected codebook. Information of the maximum channel quality indicator is sent to the base station together with a precoder of the user equipment. The base station selects user equipments based on the information of the maximum channel quality indicator and precoder, and transmits precoder signal and data signal to the user equipments. The present invention also provides a system for the base station that causes the base station to perform the above mentioned operations.

A communications apparatus is provided. A first radio module provides a first wireless communications service and communicates with a first communications device in compliance with a first protocol. A second radio module provides a second wireless communications service and communicates with a second communications device in compliance with a second protocol. A Co-Located Coexistence radio manager detects activities of the first radio modules, obtains a first traffic pattern describing downlink and / or uplink traffic allocations of the first radio module from the first radio module, and generates a second traffic pattern of the second radio module according to the first traffic pattern to coordinate operations of the first and second radio modules. The second traffic pattern describes recommended downlink and / or uplink traffic allocations to a plurality of sub-frames for the second radio module, and each sub-frame defined by the second protocol includes Orthogonal Frequency Division Multiplexing symbols.

An apparatus and method for transmitting / receiving data in a mobile communication system using multiple antennas are provided. A receiver estimates a fading channel of received data, selects a weight set relative to a maximum data transmission rate from at least one weight set with elements of a plurality of orthogonal weight vectors, and transmits feedback information including the selected weight set and channel-by-channel state information to a transmitter. The transmitter demultiplexes data to be transmitted on a basis of the feedback information into at least one sub-data stream, multiplies each sub-data stream by an associated weight, and transmits the data.

A rate-adaptive method of communicating over a multipath wireless communication system uses multiple links such that each end of a link uses multiple transmit and receive antennas. A number of independent streams that are to be transmitted for each link is determined based on an overall system performance measure. In addition, the system may also jointly determine the best modulation, coding, power control, and frequency assignment for each link, based on an overall system performance measure. In OFDM systems, the number of independent streams, as well as the modulation, coding, and power control, may be determined on a tone-by-tone basis based on an overall system performance measure.

A cellular radio communication system is provided for transmitting data over a plurality of transmission links. The system includes means for generating a modulated signal by applying a constant amplitude envelope modulation scheme to data to be transmitted across poor quality transmission links and amplifier means for non-linearly amplifying the modulated signal. The system can additionally include means for generating a second modulated signal by applying an amplitude dependent modulation scheme to data to be transmitted across higher quality transmission links and amplifier means for linearly amplifying the second modulated signal. Using a constant amplitude envelope modulation scheme, such as GMSK or MLCAM for poorer quality links means that for these links signals can be amplifier non-linearly at higher gains.

An apparatus and method for cooperative relay in a multiple-antenna wireless communication system based on relay stations (RSs) are provided. The apparatus includes a serial / parallel converter for dividing data into N number of streams, a channel estimator for calculating a first transmission rate at which a RS performing the cooperative relay can perform decoding and a second transmission rate at which all relay stations performing the cooperative relay can commonly perform decoding, and determining transmission rates for each of the N-number streams, and an adaptive modulation and coding (AMC) unit for encoding and modulating the N-number streams according to their respective transmission rates.

A receiver circuit suppresses effects of “benign” impairment from the calculation of received signal quality estimates, such that the estimate depends primarily on the effects of non-benign impairment. For example, a received signal may be subject to same-cell and other-cell interference plus noise, which is generally modeled using a Gaussian distribution, and also may be due to certain forms of self-interference, such as quadrature phase interference arising from imperfect derotation of the pilot samples used to generate channel estimates for the received signal. Such interference generally takes on a distribution defined by the pilot signal modulation, e.g., a binomial distribution for binary phase shift keying modulation. Interference arising from such sources is relatively “benign” as compared to Gaussian interference and thus should be suppressed or otherwise discounted in signal quality calculations. Suppression may be based on subtracting benign impairment correlation estimates from total impairment correlation estimates, or on filtering the benign impairment in channel estimation.

For an incremental redundancy (IR) transmission in a MIMO system, a transmitter processes (e.g., encodes, partitions, interleaves, and modulates) a data packet based on a selected rate to obtain multiple data symbol blocks. The transmitter transmits one data symbol block at a time until a receiver correctly recovers the data packet or all blocks are transmitted. Whenever a data symbol block is received from the transmitter, the receiver detects a received symbol block to obtain a detected symbol block, processes (e.g., demodulates, deinterleaves, re-assembles, and decodes) all detected symbol blocks obtained for the data packet, and provides a decoded packet. If the decoded packet is in error, then the receiver repeats the processing when another data symbol block is received for the data packet. The receiver may also perform iterative detection and decoding on the received symbol blocks for the data packet multiple times to obtain the decoded packet.