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..

Great expectations: the value of spatial diversity in wireless networks

Abstract: The effect of spatial diversity on the throughput and reliability of wireless networks is examined. Spatial diversity is realized through multiple independently fading transmit/receive antenna paths in single-user communication and through independently fading links in multiuser communication. Adopting spatial diversity as a central theme, we start by studying its information-theoretic foundations, then we illustrate its benefits across the physical (signal transmission/coding and receiver signal processing) and networking (resource allocation, routing, and applications) layers. Throughout the paper, we discuss engineering intuition and tradeoffs, emphasizing the strong interactions between the various network functionalities.

Downlink Cellular Network Analysis With Multi-Slope Path Loss Models

Abstract: Existing cellular network analyses, and even simulations, typically use the standard path loss model where received power decays like $\Vert x\Vert^{-\alpha}$ over a distance $\Vert x\Vert$ . This standard path loss model is quite idealized, and in most scenarios the path loss exponent $\alpha$ is itself a function of $\Vert x\Vert$ , typically an increasing one. Enforcing a single path loss exponent can lead to orders of magnitude differences in average received and interference powers versus the true values. In this paper, we study multi-slope path loss models, where different distance ranges are subject to different path loss exponents. We focus on the dual-slope path loss function, which is a piece-wise power law and continuous and accurately approximates many practical scenarios. We derive the distributions of SIR, SNR, and finally SINR before finding the potential throughput scaling, which provides insight on the observed cell-splitting rate gain. The exact mathematical results show that the SIR monotonically decreases with network density, while the converse is true for SNR, and thus the network coverage probability in terms of SINR is maximized at some finite density. With ultra-densification (network density goes to infinity), there exists a phase transition in the near-field path loss exponent $\alpha_{0}$ : if $\alpha_{0} >1$ unbounded potential throughput can be achieved asymptotically; if $\alpha_{0} , ultra-densification leads in the extreme case to zero throughput.

Reduced jamming between receivers and wireless power transmitters

Abstract: Exemplary embodiments are directed to reducing jamming caused by radiated fields generated by wireless power transmitters. Exemplary embodiments include detecting a jamming condition of a wireless power receiving device resulting from a radiated field from a wireless power transmitter of a charging device. Such embodiments include synchronizing the wireless power coupling with communication of the wireless power receiving device. Synchronizing wireless power coupling may include wireless power coupling at a first level when the wireless power receiving device is expected to receive a signal on a communication channel. Synchronizing wireless power coupling may further include coupling at a higher rate when the wireless power receiving device is not expected to receive a signal on the communication channel.

Positioning for WLANS and other wireless networks

Abstract: Techniques for positioning access points and terminals in WLANs and other wireless networks are described. For access point positioning, measurements are obtained for at least one access point in a WLAN. The measurements may be based on transmission sequences (e.g., beacon frames) transmitted periodically by each access point. The measurements may be made by multiple terminals at different locations or a single mobile terminal at different locations. The location of each access point is determined based on the measurements and known locations of the terminal(s). For terminal positioning, measurements for at least one access point in a WLAN are obtained. The location of the terminal is determined based on the measurements and known location of each access point. The measurements may be round trip time (RTT) measurements, observed time difference (OTD) measurements, time of arrival (TOA) measurements, signal strength measurements, signal quality measurements, etc.

Design Issues and Considerations for Low-Cost 3-D TSV IC Technology

Abstract: In this paper key design issues and considerations of a low-cost 3-D Cu-TSV technology are investigated. The impact of TSV on BEOL interconnect reliability is limited, no failures have been observed. The impact of TSV stress on MOS devices causes shifts, further analysis is required to understand their importance. Thermal hot spots in 3-D chip stacks cause temperature increases three times higher than in 2-D chips, necessitating a careful thermal floorplanning to avoid thermal failures. We have monitored for ESD during 3-D processing and have found no events take place, however careful further monitoring is required. The noise coupling between two tiers in a 3-D chip-stack is 20 dB lower than in a 2-D SoC, opening opportunities for increased mixed signal system performance. The impact on digital circuit performance of TSVs is accurately modeled with the presented RC model and digital gates can directly drive signals through TSVs at high speed and low power. Experimental results of a 3-D Network-on-Chip implementation demonstrate that the NoC concept can be extended from 2-D SoC to 3-D SoCs at low area (0.018 ) and power (3%) overhead.