Qualcomm

About: Qualcomm is a company organization based out in Farnborough, United Kingdom. It is known for research contribution in the topics: Wireless & Signal. The organization has 19408 authors who have published 38405 publications receiving 804693 citations. The organization is also known as: Qualcomm Incorporated & Qualcomm, Inc..

System and method for utilizing a wireless communications device

Abstract: A system and method for determining the identity of a product and then calculating an offer price for the product are disclosed The identity of the product may be determined using near-field communication in one aspect The system and method are operable to enable retailers to provide a lowest price for the product and conduct a series of offer calculations to determine an offer for a consumer The offer is based, in part, on costs to the consumer in executing the transaction (eg, travel time, fuel, etc) The offer may be higher than the lowest price as determined by each retailer, respectively, while still providing a discount to the consumer to entice a purchase of the product

A wavelength rerouting algorithm in wide-area all-optical networks

Abstract: This paper considers rerouting and minimization of incurred disruption due to rerouting in a wide-area all-optical wavelength division multiplexed (WDM) network with random circuit arrivals and departures. One limitation of such a network is the wavelength continuity constraint imposed by the all-optical cross-connect switches which do not allow a circuit to be placed on a nonwavelength-continuous route. Wavelength rerouting is proposed to rearrange certain existing circuits to create a wavelength-continuous route in order to accommodate a new circuit. To reduce the disruption period, move-to-vacant wavelength-retuning (MTV WR) is used as the basic operation of circuit migration, in which a circuit is moved to a vacant wavelength on the same path, and parallel MTV WR rerouting is used to reroute multiple circuits. An optimal algorithm is developed to minimize the weighted number of rerouted circuits with parallel MTV WR rerouting. In our test network, wavelength rerouting can effectively alleviate the wavelength continuity constraint by reducing call blocking probability an average of 30 % while reducing the number of rerouted circuits and the disruption period,.

An integrated LMS adaptive filter of TX leakage for CDMA receiver front ends

Abstract: The theory and practical implementation of a continuous-time LMS adaptive filter of the TX leakage in CDMA receivers are described. The filter works by injecting a matched out-of-phase copy of the TX leakage into the LNA output. It requires a reference signal coupled from the TX chain, whose I and Q components are appropriately scaled to generate the matched copy. The scale factors are the results of the correlation between the filter output signal and the I/Q components of the reference signal. The filter was designed as part of a 0.25-/spl mu/m CMOS cellular-band receiver. The effect of the DC offsets in the correlators on the TX leakage rejection ratio (TXRR) was minimized by using the sign-data variant of the LMS algorithm and by increasing the gain of the correlating multipliers. The loop stability margin was improved by swapping the I and Q reference inputs of the scaling multipliers. Without a significant group delay of the TX leakage relative to the reference signal, the filter achieved the maximum TXRR of 28 dB, which was limited by the reference signal coupling. The group delay introduced by the SAW duplexer reduced the minimum TXRR to 10.8 dB. The filter degraded the LNA noise factor and gain by 1.3 dB and 1.7 dB, respectively.

Methods and apparatus for encoding LDPC codes

Abstract: Methods and apparatus for encoding codewords which are particularly well suited for use with low density parity check (LDPC) codes and long codewords are described. The described methods allow encoding graph structures which are largely comprised of multiple identical copies of a much smaller graph. Copies of the smaller graph are subject to a controlled permutation operation to create the larger graph structure. The same controlled permutations are directly implemented to support bit passing between the replicated copies of the small graph. Bits corresponding to individual copies of the graph are stored in a memory and accessed in sets, one from each copy of the graph, using a SIMD read or write instruction. The graph permutation operation may be implemented by simply reordering bits, e.g., using a cyclic permutation operation, in each set of bits read out of a bit memory so that the bits are passed to processing circuits corresponding to different copies of the small graph.

Feedback and rate adaptation for mimo transmission in a time division duplexed (tdd) communication system

Abstract: Techniques for sending a MIMO transmission in a wireless communication system are described. In one design, a transmitter sends a first reference signal to a receiver. The receiver selects a precoding matrix based on the first reference signal and in accordance with a selection criterion. The receiver estimates noise and interference at the receiver and determines channel quality indicator (CQI) or modulation and coding scheme (MCS) information based on the precoding matrix and the estimated noise and interference. The receiver sends the CQI or MCS information and a second reference signal to the transmitter. The transmitter selects the precoding matrix based on the second reference signal and in accordance with the same selection criterion used by the receiver. The transmitter then sends a MIMO transmission to the receiver based on the CQI or MCS information obtained from the receiver and the precoding matrix selected by the transmitter.