Agere Systems

About: Agere Systems is a based out in . It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 3145 authors who have published 3588 publications receiving 68657 citations.

Cache decay: exploiting generational behavior to reduce cache leakage power

Abstract: Power dissipation is increasingly important in CPUs ranging from those intended for mobile use, all the way up to high-performance processors for high-end servers. While the bulk of the power dissipated is dynamic switching power, leakage power is also beginning to be a concern. Chipmakers expect that in future chip generations, leakage's proportion of total chip power will increase significantly.This paper examines methods for reducing leakage power within the cache memories of the CPU. Because caches comprise much of a CPU chip's area and transistor counts, they are reasonable targets for attacking leakage. We discuss policies and implementations for reducing cache leakage by invalidating and “turning off” cache lines when they hold data not likely to be reused. In particular, our approach is targeted at the generational nature of cache line usage. That is, cache lines typically have a flurry of frequent use when first brought into the cache, and then have a period of “dead time” before they are evicted. By devising effective, low-power ways of deducing dead time, our results show that in many cases we can reduce LI cache leakage energy by 4x in SPEC2000 applications without impacting performance. Because our decay-based techniques have notions of competitive on-line algorithms at their roots, their energy usage can be theoretically bounded at within a factor of two of the optimal oracle-based policy. We also examine adaptive decay-based policies that make energy-minimizing policy choices on a per-application basis by choosing appropriate decay intervals individually for each cache line. Our proposed adaptive policies effectively reduce LI cache leakage energy by 5x for the SPEC2000 with only negligible degradations in performance.

A 220 mW 1 Gb/s 1024-bit rate-1/2 low density parity check code decoder

Abstract: A 1024-b, rate-1/2, soft decision low-density parity-check (LDPC) code decoder has been implemented that matches the coding gain of equivalent turbo codes. The decoder features a parallel architecture that supports a maximum throughput of 1 Gb/s while performing 64 decoder iterations. The parallel architecture enables rapid convergence in the decoding algorithm to be translated into low decoder switching activity resulting in a power dissipation of only 690 mW from a 1.5-V supply.

Wireless communication module system and method for performing a wireless communication

Abstract: The present invention provides a wireless communication module system for use with a portable personal computer (PC) having a motherboard and an integral display screen In one embodiment, the system includes a single wired interface having first and second ends, where the first end is coupled to the motherboard and the second end is coupled to the display screen and provides a connection port The system further includes a wireless communication module having an antenna and an interface port removably coupled to the connection port In this embodiment, the module also includes a transceiver configured to employ the antenna to transmit and receive radio communication signals, where the transceiver is further configured to employ the interface port to communicate with the motherboard A method for performing a wireless communication and a wireless communication system incorporating the wireless communication module system or the method are also disclosed

Binaural cue coding-Part II:Schemes and applications

Abstract: Binaural Cue Coding (BCC) is a method for multichannel spatial rendering based on one down-mixed audio channel and side information. The companion paper (Part I) covers the psychoacoustic fundamentals of this method and outlines principles for the design of BCC schemes. The BCC analysis and synthesis methods of Part I are motivated and presented in the framework of stereophonic audio coding. This paper, Part II, generalizes the basic BCC schemes presented in Part I. It includes BCC for multichannel signals and employs an enhanced set of perceptual spatial cues for BCC synthesis. A scheme for multichannel audio coding is presented. Moreover, a modified scheme is derived that allows flexible rendering of the spatial image at the receiver supporting dynamic control. All aspects of complete BCC encoder and decoder implementations are discussed, such as down-mixing of the input signals, low complexity estimation of the spatial cues, and quantization and coding of the side information. Application examples are given and the performance of the coder implementations are evaluated and discussed based on subjective listening test results.