In this paper, we introduce an LDPC decoder design for decoding a length-672 multi-rate code adopted in IEEE 802.15.3c standard. The proposed decoder features high performances in both data rate and power efficiency. A macro-layer level fully parallel layered decoding architecture is proposed to support the throughput requirement in the standard. For the proposed decoder, it takes only 4 clock cycles to process one decoding iteration. While parallelism increases, the chip routing congestion problem becomes more severe because a more complicated interconnection network is needed for message passing during the decoding process. This problem is nicely solved by our proposed efficient message permutation scheme utilizing exploited parity check matrix features. The proposed message permutation network features high compatibility and zero-logic-gate VLSI implementation, which contribute to the remarkable improvements in both area utilization ratio and total gate count. Meanwhile, frame-level pipeline decoding is applied in the design to shorten the critical path. To verify the above techniques, the proposed decoder is implemented on a chip fabricated using Fujitsu 65 nm 1P12L LVT CMOS process. The chip occupies a core area of 1.30 mm2 with area utilization ratio 86.3%. According to the measurement results, working at 1.2 V, 400 MHz and 10 iterations the proposed decoder delivers a 6.72 Gb/s data throughput and dissipates a power of 537.6 mW, resulting in an energy efficiency 8.0 pJ/bit/iteration. Moreover, a decoder of the same architecture but with no pipeline stage for low-profile application is also implemented and evaluated at post-layout level.

We propose a new modulation, phase-silence-shift-keying (PSSK), whose symbol error rate (SER) performance is improved by 6 dB compared with phase-shift-keying (PSK). To prove this, theoretical analysis of probability of error is provided and simulation results are presented.

Power efficiency and real-time processing capability are two major issues in today's mobile video applications. We proposed a novel Motion Estimation (ME) engine for power-efficient real-time MPEG-4 video coding based on our previously proposed content-based ME algorithm [8],[13]. By adopting Full Search (FS) and Three Step Search (TSS) alternatively according to the nature of video contents, this algorithm keeps the visual quality very close to that of FS with only 3% of its computational power. We designed a flexible Block Matching (BM) Unit with 16-PE SIMD data path so that the adaptive ME can be performed at a much lower clock frequency and hardware cost as compared with previous FS based work. To reduce the energy cost caused by excessive external memory access, on-chip SRAM is also utilized and optimized for parallel processing in the BM Unit. The ME engine is fabricated with TSMC 0.18 µm technology. When processing QCIF (15 fps) video, the estimated power is 2.88 mW@4.16 MHz (supply voltage: 1.62 V). It is believed to be a favorable contribution to the video encoder LSI design for mobile applications.