Gi Yoon Park

An improved implementation method of the gold sequence generator

Conventional GSG (gold sequence generator) creates only 1 bit data per clock cycle. Therefore it may cause delay to the data communications. In this paper, we propose an efficient implementation method of the GSG for high speed data communications. Through simple matrix multiplications, we could not only derive a well-organized recursive formula but also implement the GSG with parallel outputs. Experimental results show that though the total area and clock period of the proposed scheme are 3~13% and 21~23% larger than those of the existing scheme respectively, our GSG improves 2, 4 and 6 times the throughput compared with the existing GSG when the modulation orders are QPSK, 16-QAM and 64-QAM respectively.

Automatic gain control for ASM channel in maritime communication

This paper presents Automatic Gain Control (AGC) algorithm in maritime communication system using application specific message (ASM). In maritime communication, gain control is not easy than land mobile communication. Received signal is converted to digital signal by analog to digital converter (ADC). If the signal input power of ADC is smaller than adequate power then quantization noise increases. On the contrary, if the signal input power of ADC is large than adequate power then the output signal of ADC is saturated. This paper proposes essential algorithm that controls gain value effectively in case that received signal power and propagation delay are unknown. We first analyze the general method of AGC in maritime communication. The analysis will show that the time for gain convergence is needed and much longer than known case because the distance from transmitting ship to receiving ship is randomly distributed and unknown in each slot. The difference of gain values in each slot is as large as 100dB in maximum case. The larger a difference of gain values is, the longer gain convergence time is. This is because that any ship can transmit in any slot randomly, therefore, received signal power is not expectable. We show how proposed algorithm can effectively control the gain value in maritime communication environments. Result of simulation shows that the utilization of proposed algorithm can calculate the optimal gain value and regenerate optimal signal that is similar with original source. As a result, proposed AGC algorithm changes all gain values of total received signal into same gain value using back gain compensation. Especially, the gain value of received signal should be controlled in adequate because transmission randomly occurs in each slot in maritime communication. Proposed automatic gain control algorithm is essential and effective for stable demodulation performance in ASM maritime communication.

An Implementation of GSG with Parallel Outputs Targeting MIMO Detector

Existing GSG (gold sequence generator) generates only 1 bit data per clock cycle. Thus it may cause delay to the data communications. In this paper, we propose the GSG with parallel outputs for high speed data communications. Through simple matrix multiplications, we could not only derive a recursive formula in parallel form but also implement the GSG with multiple outputs. Experimental results show that though the total area and clock period of the proposed scheme are 3~13% and 21~23% larger than those of the existing scheme, our GSGs with parallel outputs improve 2, 4 and 6 times the throughput, respectively, compared with the existing GSG with single output. We also applied our GSGs to a MMSE-SIC receiver for MIMO-OFDMA systems. Therefore, we remarkably improve the throughput of the MIMO detector with the parallel processing of the data communications.

Development of an ASM2.0 RF system for maritime communications of high-data-rate in the VHF band

This paper presents a development of a RF system for the application specific message 2.0 (ASM2.0) which is a new maritime communication service in the VHF band. It contains a specification determination related to a RF system, some design points to support a complex modulation scheme for high-data-rate, and the implementation results. And, performances linked with a baseband (BB) system are also described.

Signal detection for orthogonal space-time block codes without trancevier linearization property

This paper addresses signal detection problems for orthogonal space-time block codes (OSTBC) without a transceiver signal linearization property, especially when a quasi-static channel condition does not hold. By augmenting transceiver a model with its complex conjugate, well-established multiple-input multiple-output (MIMO) detection techniques become applicable for the problem. We consider zero-forcing (ZF) detection for inter-symbol interference cancellations.