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..

Asymptotic analysis of multistage cooperative broadcast in wireless networks

Abstract: Cooperative broadcast aims to deliver a source message to a locally connected network by means of collaborating nodes. In traditional architectures, node cooperation has been at the network layer. Recently, physical layer cooperative schemes have been shown to offer several advantages over the network layer approaches. This form of cooperation employs distributed transmission resources at the physical layer as a single radio with spatial diversity. In decentralized cooperation schemes, collaborating nodes make transmission decisions based on the quality of the received signal, which is the only parameter available locally. In this case, critical parameters that influence the broadcast performance include the source/relay transmission powers and the decoding threshold (the minimum signal-to-noise ratio (SNR) required to decode a transmission). We study the effect of these parameters on the number of nodes reached by cooperative broadcast. In particular, we show that there exists a phase transition in the network behavior: if the decoding threshold is below a critical value, the message is delivered to the whole network. Otherwise, only a fraction of the nodes is reached, which is proportional to the source transmit power. Our approach is based on the idea of continuum approximation, which yields closed-form expressions that are accurate when the network density is high.

Data transmission with non-uniform distribution of data rates for a multiple-input multiple-output (mimo) system

Abstract: Techniques to determine data rates for a number of data streams transmitted via a number of transmission channels (or transmit antennas) in a multi-channel (e.g., MIMO) communication system. In one method, the “required” SNR for each data rate to be used is initially determined, with at least two data rates being unequal. The “effective” SNR for each data stream is also determined based on the received SNR and successive interference cancellation processing at the receiver to recover the data streams. The required SNR for each data stream is then compared against its effective SNR. The data rates are deemed to be supported if the required SNR for each data stream is less than or equal to its effective SNR. A number of sets of data rates may be evaluated, and the rate set associated with the minimum received SNR may be selected for use for the data streams.

Portable communication device and accessory system

Abstract: A portable communications device and accessory system which enables both voice and control commands to be communicated between a portable communication device and external accessories over a single flexible digital interface. When the portable communication device is interfaced to external accessories, such as a power booster and hands-free kit, a microprocessor configures the serial communications bus to pass both the digital voice data and digital control commands to and from the external power booster and the hands-free kit. The external hands-free kit contains its own auxiliary CODEC for encoding analog voice signals and decoding the digital voice data. When the portable communication device is not interfaced with external accessories, the microprocessor configures the serial communication bus to pass the digital voice data to and from an internal CODEC for use with the portable device's own microphone and speaker.

Distributed hierarchical scheduling in an ad hoc network

Abstract: An ad hoc network with distributed hierarchical scheduling is disclosed. In one aspect, stations in a network mesh detect interfering neighbor stations and form interference lists. Stations transmit their interference lists. Scheduling stations schedule allocations for child stations in response to interference lists, received remote allocations, or a combination thereof. Coordination messages are transmitted including frame structure, allocations, and interference lists, among others. In another aspect, an ad hoc mesh network may be organized into a tree topology. In an example wireless backhaul network, this matches traffic flow. Distributed, hierarchical scheduling is provided where parents schedule communication with children while respecting already scheduled transmissions to/from interferers and to/from interferers of their respective children. Procedures to construct interference constraints for distributed, hierarchical scheduling are described, resulting in efficient scheduling and reuse in an ad hoc wireless network, without centralized scheduling. Various other aspects are also disclosed.

Power control for a channel with multiple formats in a communication system

Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.