Sangsung Choi

A low-power CMOS power amplifier for ultra wideband (UWB) applications

This paper presents the design and implementation of a wideband power amplifier for UWB applications, covering the lower band frequencies of 3.1 GHz to 4.8 GHz. To achieve sufficient linearity and efficiency, this PA operates in the class-AB regime, delivering an output power of -4.2 dBm at an input 1 dB compression point of -22 dBm for a 4 GHz signal. This PA has a differential input and a single-ended output that has been matched to 50 /spl Omega/ at both ends. Complete design and implementation was done using TSMC 0.18 /spl mu/m CMOS technology and it consumes a very low power of 25 mW, while realizing a flat gain of 19/spl plusmn/1 dB across the whole band of operation.

A systematic approach to CMOS low noise amplifier design for ultrawideband applications

In this paper, we introduce a systematic method to design CMOS low noise amplifiers (LNA) for ultrawideband (UWB) applications. The proposed method is addressed to optimize noise performance and power efficiency while maintaining good input and output matching. The synthesized LNA achieves up to 14 dB power gain with a low noise figure (NF) of 2 dB and provides a reasonably acceptable input and output matching of -10 dB across the frequency range of 3/spl sim/5 GHz. The developed LNA, implemented in TSMC 0.18 /spl mu/m CMOS technology, is a single-stage architecture with very low power dissipation of 9 mW with a 0.9 V supply.

An enhanced MAC protocol of IEEE 802.15.4 for wireless body area networks

As the demand for personalized service increases, many researchers are interested in the wireless body area network (WBAN) including in-body and on-body communications. This paper provides an enhanced MAC framework based on IEEE 802.15.4 which may be one of the promising technologies for WBAN. The proposed scheme covers the functions of polling access, emergency transmission, and 2-hop network extension considering in-body and on-body communication environments. Also we set up test environment to operate the proposed MAC scheme.

Phase rotation shift keying for low power and high performance WBAN in-body systems

In this paper, we propose a new modulation scheme for low power and high performance WBAN in-body communication systems. Simulation results are presented in terms of performance and transmit power. The proposed modulation scheme is more appropriate for high data rate human body applications than other schemes due to the better characteristic of spectral re-growth in the non-linear system environment as well as better performance.

QoS routing for distributed MAC-based high rate wireless personal area networks

QoS routing for a TDMA-based HR-WPAN requires bandwidth (time slots) to be reserved on the entire path. Depending on the way of route discovery and bandwidth reservation, QoS routing can be classified into two types: on-demand (reactive) and table-driven (proactive). Simulation results indicate that table-driven QoS routing outperforms on-demand QoS routing when average hop count is large. When average hop count is small, vice versa. Two QoS routing protocols can also be integrated to enhance overall performance. Hybrid QoS routing begins with table-driven QoS routing and, if necessary, switches later on to on-demand QoS routing. By combining proactive and reactive features, hybrid QoS routing maintains network performance satisfactorily regardless of average hop count.

MAC hardware platform for on-body WBAN applications

This paper shows the design of MAC hardware platform based on IEEE 802.15.6 for on-body WBAN applications. Considering beacon mode with sperframe boundaries, several types of access functions are implemented such as random access and scheduled accesses. And high resolution timers and status control logics are embedded in the FPGA devices for the operation of Tx and Rx control, protocol control, and several interfaces.

Signal modeling of BC-GPPM for WBAN communication based on IEEE 802.15.6

In this paper, we propose signal-modeling of the block-coded group pulse position modulation (BC-GPPM) for the wireless body area network (WBAN). The BC-GPPM is one of modulation methods for the WBAN application taking the technical requirements such as data-rate scalability, low complexity and low-power. This paper describes concept of WBAN non-coherent standard related to BC-GPPM and proposes a BC-GPPM signal-modeling derived from the conventional pulse position modulation (PPM).

Non-coherent synchronization for WBAN UWB systems

This paper presents non-coherent synchronization method for UWB WBAN systems. The non-coherent synchronization including packet detection and SFD detection is described and packet error rate performance in AWGN is provided. Finally, we make a conclusion in view of the implemental aspect.