Hyun Kyun Choi

Performance evaluation of V2V/V2I communications: The effect of midamble insertion

In vehicular communications, the channel estimation is critical to compensate signal distortion due to wireless channel in high mobility scenario. To improve the error performance of vehicular communications, we proposed the midamble-based channel estimation scheme [12]. Based on the proposed scheme, we investigate the effect of midamble insertion on the system performance. With various midamble insertion rates, the error performance for the system with different modulation scheme, packet size, and channel condition is explored. The effects of various factors on the error performance are also developed.

Mid-amble aided OFDM performance analysis in high mobility vehicular channel

In this paper, we present mid-amble aided channel estimation and its performance analysis of OFDM signal in high mobility vehicular radio channel. Preamble and pilot subcarriers are used for initial acquisition and channel estimation in WAVE system. In case of long sized packets, the performance is degraded in high mobility radio channel. The proposed mid-amble aided channel estimation gives the improved performance over conventional Preamble and Pilot subcarriers aided channel estimation methods.

Realization of anti-collision warning application using V2V communication

Vehicular communications provide new convergence applications by combining vehicles and communication technologies. In this paper, we consider the anti-collision warning application using vehicle-to-vehicle (V2V) communication. First, we introduce the general and special features of the overall system and specifications of the communication prototype. Then, we investigate the application scenarios and communication algorithms including practical measurement results. Some implementation issues of vehicular communications are also addressed.

Optimum relay node selection for two-relay networks in railway environments

Relay networks enhance the system performance by creating cooperative diversity gain and extend communication range by relaying the received signal to other devices. Recently, Long Term Evolution-Railway (LTE-R) is applied in railway communication to increase capacity by keeping reliability, and 3rd Generation Partnership Projects (3GPP) adopts relay function for data transmission. In this paper, the performance of two-relay networks is analyzed in railway environments. We adopt decode-and-forward (DF) protocol for relaying using partially differential modulation to bypass channel estimation at the destination. We first analyze the effect of relay location in the system performance. Based on this, we find the optimum relay selection which minimizes the symbol error rate (SER).

Performance analysis of Vehicle Multi-hop Communication (VMC) Technology

We introduce vehicle multi-hop communication (VMC) project in Korea, which provides vehicle to vehicle and vehicle to Infra communications. At first, technical issues such as high mobility, low packet latency and high density are discussed. And we propose Mid-amble based channel estimation and hybrid MAC for vehicle safety and traffic information applications. Mid-amble based channel estimation is effective for long packet transmission and hybrid MAC has better performance for high density user environments. To show the merits of the proposed technologies, radio link performance is analyzed in high mobility radio channel by computer simulation.