Nguyen Huy Hoang

End-to-end channel capacity of MAC-PHY cross-layer multiple-hop MIMO relay system with outdated CSI

For high end-to-end channel capacity, the amplify-and-forward scheme multiple-hop multiple-input multiple-output relay system is considered. The distance between each transceiver and the transmit power of each relay are optimized to prevent some relays from being the bottleneck and guarantee high end-to-end channel capacity. According to the proposed transmission environment coefficient, the path loss can be described in a new way, and then the distance of multiple-hop relay system can be optimized more simply than the original one. However, when the system has no control on media access control (MAC) layer, performance of the system deteriorates because of the presence of interference signal. Thus, the specific transmission protocol on the MAC layer for multiple-hop system is proposed to reduce the power of interference signal and to obtain high end-to-end channel capacity. According to the proposed transmission protocol on the MAC layer, the system indicates the trade-off between the end-to-end channel capacity and the delay time. The end-to-end channel capacity of the outdated channel state information system is also analyzed.

End-to-end channel capacity of multiple-hop MIMO relay system with MAC-PHY cross-layer

For high end-to-end channel capacity, the amplify-and-forward scheme multiple-hop MIMO relays system is considered. The distance between each transceiver and the transmit power of each relay node are optimized to prevent some relays from being the bottleneck and guarantee the high end-to-end channel capacity. By proposing the transmission environment coefficient, the path loss is described in a new way and then the distance of multiple-hop relay system can be optimized more simply than the original one. However, when the system has no control on Mac layer, the performance of system is deteriorated because of the presenting of interference signal. Thus the specific control protocol on MAC layer for multiple-hop system is proposed to reduce the power of interference signal and obtain the high end-to-end channel capacity. According to proposed control protocol on MAC layer, the system indicates the trade-off between the end-to-end channel capacity and the delay time.

Study of injection locking effect in terahertz resonant tunneling diode oscillators

In this article the injection locking effect in terahertz (THz) resonant tunneling diode (RTD) oscillators is studied using a circuit simulation method. The simulation model is implemented in a popular simulator called Keysight ADS for ease of use and effective investigation. The locking phenomenon is successfully observed. Pulling range, locking range, locking conditions and influence of antenna resistance on locking range of the effect are carefully discussed. We found that locking range is wide, locking effect can be occurred at a relatively low injected power and injection locked RTD THz oscillator array is feasible.

Payload and power consumption analysis of IEEE802.15.6 based WBAN with CSMA/CA

According to emergency of wireless body area network (WBAN), the IEEE802.15.6 standard was established in Feb. 2012. A physical (PHY) layer, medium access control (MAC) layer and network layer were almost decided, however a payload in every packet is varied within [0,250] bytes. Since the low influence on human body and the low transmit power are required, the received signal to noise ratio (SNR) of coordinator depends on distances between sensors and the coordinator and varies in a larger region. Therefore, the assumption of noise free is no longer available. The discrete time Markov chain method (DTMC) is proposed to calculate the access probability of every sensor and analyze the performance of system with regard to packet error rate. The calculation method of power consumption is also proposed to correctly estimate the power consumption of WBANs that adopt the carrier sense multiple access with collision avoidance (CSMA/CA) as a transmission protocol. The payload is optimized for every Eb/N0 in order to obtain the best energy efficiency. The calculation result indicates that the optimal payload decreases when the Eb/N0 decreases while the total data which a sensor should transmit to the coordinator is being fixed, whereas the optimal payload increases slightly in low Eb/N0 region when the total data increases.

On channel capacity of two-way multiple-hop mimo relay system with specific access control

For the high end-to-end channel capacity, the amplify-and-forward (AF) scheme multiple-hop MIMO relays system is considered. The distance between each transceiver and the transmit power of each relay node are optimized to prevent some relays from being the bottleneck and guarantee the high end-to-end channel capacity. However, when the system has no control on Mac layer, the interference signal should be taken in account and then the performance of system is deteriorated. Therefore, the specific access control on MAC layer is proposed to obtain the higher end-to-end channel capacity. The optimum number of relays for the highest channel capacity is obtained for each access method. However, there is the trade-off of channel capacity and delay time.

Optimizing Relay Selection in Distributed MIMO Relay System for Conservation of Transmit Power

The research on distributed MIMO relay system has been attracting much attention. By optimizing the position of each relay, the channel capacity of such system is larger than that of original MIMO system. However, the propagation environment between each transceiver is simplified to be the same. In this paper, a decode-and-forward scheme distributed MIMO relay system is examined. The distance between each relay is optimized in propagation environment which is brought close to actuality. For upper bound of channel capacity, the number of relay is optimized whether total antenna element is fixed or not. When the number of relay is assumed to be infinite, the dynamic relay selection method based on the transmission rate is proposed. We represent that with such method the transmit power and relay is saving.