Optimal Cooperative MIMO Scheme in Wireless Sensor Networks

Cooperative Multiple-Input Multiple-Output (MIMO) has been proposed as a transmission strategy to combat the fading problem in Wireless Sensor Networks (WSNs) to reduce the retransmission probability and lower the transmission energy. Among the earliest work on cooperative MIMO in WSNs is the analysis of the Space-Time Block Coding (STBC) scheme to achieve lower Bit Error Rate (BER) and significant energy savings. The work is continued with the implementation of the Low-Energy Adaptive Clustering Hierarchy (LEACH) Medium Access Control (MAC) protocol for clustered-based architectures. The combination of STBC and the LEACH scheme resulted in a significant improvement in transmission energy efficiency compared to the Single-Input Single Output (SISO) scheme. Further study is conducted to compare the performance of STBC and various Spatial Multiplexing (SM) schemes such as Vertical Bell Labs Layered Space-Time (V-BLAST) and Diagonal BLAST. In this study, LEACH MAC was also utilized and lower transmission energy and latency were achieved against the SISO scheme. However, the centralized architecture leads to energy wastage and higher latency compared to a distributed architecture. On the other hand, the implementation of a distributed architecture needs to consider synchronisation issues. Thus a practical cooperative MIMO scheme for distributed asynchronous WSNs is needed. Moreover, a practical MAC that can suit cooperative transmission is required. A combination of a practical MAC protocol and an efficient MIMO scheme for asynchronous cooperative transmission leads to a more energy efficient and lower latency cooperative MIMO system. A combination of a MAC protocol and a cooperative SM scheme for cooperative MIMO transmission has been proposed in previous study where the combined scheme achieves significant energy efficiency and lower latency. Furthermore, a transmit Maximum Ratio Combiner (MRC) scheme is suggested to be more tolerant to the jitter difference than the Alamouti STC scheme in network with imperfect transmitting nodes synchronisation. In this chapter, we expand these studies to two other cooperative MIMO schemes, namely Beamforming (BF) and STBC for both network scenarios: perfect and imperfect transmitting nodes synchronisation. The optimal cooperative MIMO scheme combined with an appropriate MAC protocol should lead to the lowest energy consumption and lowest packet latency

Cooperative MIMO Systems in Wireless Sensor Networks

28 page(s

Modeling and Performance Analysis of Throughput-Received Power Relationship for Indoor Wireless Mesh Network

In Wireless Mesh Network (WMN) the mesh nodes (APs) are configured with the same frequency channel creates a phenomenon called as co-channel interference. The purpose of selecting the same frequency channel is to make sure all the mesh nodes can talk each other within the frequency range. In order to study the effects of this phenomenon together with multipath fading for indoor environment, we have setup a wireless mesh network operating at 2.4GHz inside a 4-floors faculty building. Extensive measurement campaigns have been conducted at each floor. To observe the effects of these phenomena at the application layer perspective, we measure the network throughput and mapped it to the physical layer performance parameter; received power. The relationship between the application and physical layers performance parameters is modeled numerically and the results are analyzed. One interesting finding is that the empirical relationship model for wireless mesh network does not follow the common exponential models as known in Wireless Local Area Network (WLAN). We can say that the throughput drop is too small and can be neglected and the average throughput is at 1.53Mbps over all received powers. The result shows that the effects of both co-channel interference and multipath are very severe and need to be tackled properly in wireless mesh network design and deployment

The Performance Comparison Of Printed Dipole Antenna With Two Different Structures Of Amc Ground Plane

The performances of the triple-band meandered dipole antenna backed by two different Artificial Magnetic Conductor (AMC) structures are discussed in this paper. Two kinds of AMC structures are presented namely rectangular-patch with rectangular slot and rectangular-patch with slotted rectangular and I-shaped slot. The AMCs are designed to operate at 0.92GHz and 2.45GHz. The performances of the antenna with and without the dual-band AMC ground plane are investigated in terms of return loss, realized gain and power received. It clearly shows that the printed dipole antenna has a lower gain compared to the printed dipole antenna with high-impedance structure ground plane (GP). Furthermore, the received power of the dipole antenna backed by the 2x2 rectangular-patch with slotted rectangular and I-slot AMC receives a slightly higher power compared to the dipole antenna backed by the 2x2 rectangular-patch with rectangular slot AMC

Application of Genetic Algorithm for the Optimization of Energy Saving Glass Coating Structure Design

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient

Optimal coperative MIMO scheme in wireless sensor networks

16 page(s

Analysis Of Indoor MIMO Channel Capacity Using Spatial Diversity Technique

This paper focus on simulation and measurement of MIMO channel capacity for indoor propagation. A spatial diversity method is employed during measurement and simulation process. The investigation on the channel capacity for various distance and spacing of both transmitter and receiver antenna have been done. The investigations of channel capacity are included with difference distance between transmitter and receiver sides and different in element antenna spacing. For the simulation, the path loss for the free space and physical effect are been considered. The 2x2 rectangular microstrip patch array antenna is used in order to characterize channel parameter at 2.4GHz operating frequency. Measurement process for 4x4 antenna configuration is done in UTeM Microwave Laboratory. The capacities of MIMO channel also decrease by increasing the distance between transmit and receive antenna

Study on microstrip x-linear polarized and x-circular polarized antenna

This paper present an x-linear polarized microstrip patch antenna and x-circular polarized microstrip patch antenna using single port in X-form at 45 0, 135 0, 225 0 and 315 0. Combinations of 4 patches using quarter wave impedance matching technique have been used to design x-linear polarized microstrip patch antenna and x-circular polarized microstrip patch antenna. The proposed designs were simulated using Computer Simulation Technology (CST) with dielectric constant, ε r=4.3, tan δ=0.019 and thickness of substrate, t=1.6mm. The associated simulation and measurement results such as return loss, bandwidth, gain, directivity and polarization have been compared and analyzed. Both antennas have gain between 5dB to 7dB

The Effect Of Quarter-Wave Transformer Matching Network To The X-Circular Polarized Antenna

This technical paper presents the 2 design of xcircular polarized with slanted rectangular slot microstrip patch antenna by using single port in X-form is at 45 0 , 135 0 , 225 0 and 315 0 . The combination of 4 circular patches of Design 1 and the additional of quarter wave impedance matching technique for Design 2 have been used to design the X-circular polarized with slanted rectangular slot microstrip patch antenna. The designs are simulated using Computer Simulation Technology (CST) with dielectric constant, εr =4.3 and tan δ=0.019 and thickness of substrate, t=1.6mm. The simulation results such as return loss, bandwidth, gain, directivity and polarization have been compare

MIMO beamforming network having polarization diversity

This paper presents a MIMO channel measurement for indoor environment. The results present the comparison of channel capacity by using beamforming technique in MIMO systems. Also, polarization diversities (vertical and horizontal) are introduced to reduce multipath fading issues. The measurements were conducted at 2.4GHz with Line of Sight (LOS) scenario