National Semiconductor Corporation

Koninklijke Philips Corporation N.V.

Leland Stanford Junior University

Other

Nxp B.v.

Avnera Corporation

Wiviu Technology Inc.

Debarag Banerjee

Karim Nassiri Toussi

Arogyaswami J Paulraj

Rajaram Subramoniam

Pascal Gilles Renucci

Gokhan Cosgul

Huoy-Bing Lim

Systems, apparatus, and methods are provided to enhance transmitting and receiving video data streams with feedback information over a lossy and/or congested network. The systems, apparatus, and methods may optimize retransmission for lost packets or lost data frames. Optimizations are also provided to select reference frames in a data stream so that block errors are contained when RPS is used to encode data frames. Optimization in decoding may include reconstructing high-resolution data frames from low-resolution data frames.

Systems and methods for transmitting and receiving data streams with feedback information over a lossy network

Systems and methods for communicating source data between a source device and a listener device are disclosed. In an exemplary embodiment, source data is encoded by organizing at least a selected portion of source data into a data block having rows and columns. Encoded columns are formed by appending to each column error correction data derived from that column using a selected error correction code. Encoded rows are formed by appending to each row error correction data derived from that row using a selected error correct code. In an exemplary embodiment, encoded rows of source data (together with appended FEC data) and a first predetermined number of rows of FEC data are transmitted together, such that the first predetermined number of rows is less than all rows of error correction data. In an exemplary embodiment, source data is organized using interleaving.

Devices and system for exchange of digital high-fidelity audio and voice through a wireless link

A fast, low-complexity detection scheme for determining the delays and gains of different propagation paths (i.e., multi-paths) of a received WCDMA signal. The method utilizes a continuous pilot channel that is scrambled by an known pseudo-random sequence. The received signal is provided to a multi-path searcher that passes the received signal through a matched filter with a specified number of taps. The matched filter correlates the received signal with the pilot channel. The multi-path gain and delay detection is then performed, and the delays and gains are reported for use in the WCDMA system.

Method and apparatus for multi-path delay spread detection in wideband CDMA systems

In a RAKE receiver capable of detecting and combining a plurality of multipath signals, a controller for managing the assignment of the plurality of multipath signals to fingers of the RAKE receiver. The controller determines a phase difference between a selected multipath signal and a first multipath signal assigned to a first finger of the RAKE receiver and does not assign the selected multipath signal to a second finger of the RAKE receiver unless the phase difference is greater than one-half chip. If the phase difference is less that one-half chip, the controller assigns the stronger of the selected multipath signal and the first multipath signal to the first finger of the RAKE receiver. If the finger power falls below a certain threshold, the finger internal states (viz. channel estimate and delay estimate) are maintained while the output of the finger is not processed. If the finger power exceeds the threshold anytime within a specified time interval, the normal activities of the finger are restored. If the power remains lower than the threshold for that time period, the finger is deactivated.

System and method for finger management in a rake receiver

Techniques for location-assisted wireless communication use real-time location(s) of wireless transceiver(s) together with stored location-indexed channel information to improve communication over a wireless channel between the transceiver(s). The stored channel information includes channel characteristics (e.g., average power, angle-of-arrival, and time delay of multipath components) that are substantially constant in time but vary gradually as a function of location. Current transceiver location(s) are obtained and used to retrieve stored channel characteristics corresponding to the location(s). The channel information may be used at either or both transceiver(s) to improve reception and/or transmission of signals propagating over the wireless channel. For example, reception may be improved by using path angle information to perform spatially structured reception, or using path delay information to perform temporally structured reception, e.g., to assign fingers to multipath components in a RAKE receiver and/or to track time delays of multipath components.

Method of optimizing wireless communication links using stored channel characteristics of different locations

A mobile device detects downlink transmit diversity. Slot and frame timing knowledge and a downlink scrambling code are applied to pilot and synch channels of the signal. An algorithm suited for the diversity case and an algorithm suited for the non-diversity case are utilized. The output of the diversity algorithm is compared to the output of the non-diversity algorithm. The output yielding the highest energy determines whether downlink transmit diversity is applied. The detection algorithms used in both the diversity and non-diversity cases use phasors to indicate the phase difference between two channels. This phase difference is the basis for determining diversity usage.

Apparatus and method for detecting downlink transmit diversity at a mobile device

An initialization method is performed to initialize the states for producing downlink scrambling code for a wideband code division multiple access (WCDMA) mobile device. The initialization method uses an auxiliary linear feedback shift register (x-LFSR) advance the x-initial state to a new initial state that corresponds to a selected downlink scrambling code. The new initial state allows the remaining masks used for generating the downlink scrambling code to be fixed. Memory required to produce the downlink scrambling codes is therefore reduced, as it is no longer dedicated to storing the sets of masks corresponding to each of the possible downlink scrambling codes.

Method and apparatus for generation of downlink scrambling code in wideband CDMA mobile devices

A channel estimator for determining channel weighting coefficients for a finger of the RAKE receiver. The channel estimator comprises: 1) a first correlator for receiving a first pilot channel signal and correlating the first pilot channel signal with a first pilot channel chip pattern associated with the first pilot channel signal to produce an output comprising a first pilot channel symbol sequence; and 2) a first channel estimation filter capable of receiving the first pilot channel symbol sequence and generating first channel weighting coefficients. The first channel estimation filter minimizes the mean squared error of the channel estimate in the first channel weighting coefficients caused by additive noise and Doppler effects, wherein the mean squared error is minimized across a range of Doppler frequencies from 0 Hz up to a predetermined maximum Doppler frequency.

System and method for channel estimation in a radio frequency receiver

A portable communication device including a power control system which estimates E/Nby determining the variance of the noise components of PCBs that are received on the fundamental traffic channel. The power control system includes a demodulator for demodulating a BPSK modulated (or PAM) first signal from a base station, a noise variance calculation circuit that samples the perpendicular noise component of the demodulated signal to determine a noise variance, a power estimation circuit that measures the power of the demodulated signal and provides an estimate of the power of the first signal by eliminating the noise variance from the demodulated signal, and a comparator that compares the ratio of the power estimate and the noise variance to a threshold. The comparator output is a power up or power down signal to the base station.

Estimating Eb/Nt in a CDMA system using power control bits

In a heterogeneous data network including both wired and wireless/lossy links, a transport protocol method implemented at the wireless host is fully compatible with existing wired networks and wireless gateways, and requires no modification to transport protocols at existing wired hosts. The wireless host calculates a temperament parameter [] characterizing the error-proneness of the data connection and uses this parameter to determine whether error-induced losses or congestion-losses dominate the data connection [. If congestion-losses dominate the data connection, then the host uses a standard technique for acknowledging data packets []. If, on the other hand, error-induced losses dominate the connection, the host uses a modified technique for acknowledging data packets []. According to this modified technique, the wireless host sends a plurality of non-duplicate acknowledgements of a single packet whenever a packet is received after an out-of-order packet is received. By acknowledging distinct fragments of the packet, rather than identical (i.e., duplicate) acknowledgments of the packet, the acknowledgments have the effect of accelerating recovery of maximal window size at the wired host and increasing data throughput.

Data throughput over lossy communication links

An example application of the invention is directed to a mobile receiver searching pilot signals in a CDMA-based radiotelephone communications system. The receiver processes received pilot signals by first decimating those pilot signals that have a search window length that is greater than a threshold number of chips, into a plurality of sub-windows. The other pilot signals and the sub-windows are then searched using a common prioritization criteria. More specific implementations of this approach permit each search of this type to take a fixed amount of time, thereby making scheduling calculations easy to implement. Moreover, such implementations provide for all pilots to be searched equally often irrespective of window sizes, and for less likely candidates for idle handoff (pilots with longer window sizes) not to be given precedence over more likely idle handoff candidates. Also, as search results are accumulated, the amount of unsearched PN space within a window decreases, thereby decreasing the probability of finding a strong pilot and increasing the ability for more intelligent scheduling.

Pilot-signal searching with decimation reordering

For use in a digital signal processing system, a filter implementation factors in the time difference between consecutive searches for the same signal and modifies the filter depending on the time-arrival differences of consecutive search results. An example application to which the invention is particularly well adapted is in a mobile receiver for a cellular radiotelephone communications system. In accordance with the present invention, after determining a relative arrival time of data sample sets in the stream of data samples, the mobile station includes a receiver arrangement configured to filter a stream of data samples arriving at irregular intervals, to provide a relative arrival time of data sample sets in the stream of data samples, and in response to determining the relative arrival time, to filter the data sample sets using value assignments that are exponentially weighted for the data sample sets. The data sample sets are weighted more than data sample sets arriving early. In a more specific implementation, the receiver arrangement searches the data sample sets for a signal strength signal, and filters the data sample sets based on time-arrival differences of consecutive search results.

Modified filtering for asynchronous inputs

A cellular radio communication system has a number of cells covered by base stations communicating with mobile communication devices. The mobile communication device performs an idle handoff method. In the idle handoff method, the communication mobile device receives paging messages from a first base station, and initiates idle handoff from the first base station to a second base station if it is established that no other, critical idle-mode process with the first base station is being performed.

Growing community of inventors

Sunnyvale, CA, United States of America

Debarag Banerjee