Review - Challenges of mobility aware MAC protocols in WSN

© 2018 IEEE. In today\u27s smart world WSN plays an important role in IoT. The WSN nodes can be used for wildlife, patient, air quality monitoring. WSN consists of numerous sensor nodes that are connected to each other. One of the major concerns of WSN is the mobility of nodes. The mobility of the nodes creates concern to the MAC protocols that\u27s defined for WSN static nodes. Mobile-WSN demands the participated nodes to send packets with a bursty traffic, low energy consumption and reliable connection. MAC protocol is the most important in designing the WSN as MAC plays an important role regarding throughput, mobility, security and energy consumption. This paper gives a review on mobility aware protocols such as M-MAC, MA-MAC, MMH-MAC, M-Contiki, MobiIQ, MobiDisc

FPGA Implementation of Block Parallel DF-MPIC Detectors for DS-CDMA Systems in Frequency-Nonselective Channels

Multistage parallel interference cancellation- (MPIC-) based detectors allow to mitigate multiple-access interference in direct-sequence code-division multiple-access (DS-CDMA) systems. They are considered serious candidates for practical implementation showing a good tradeoff between performance and complexity. Better performance is obtained when decision feedback (DF) is employed. Although MPIC and DF-MPIC have the same arithmetic complexity, DF-MPIC needs much more FPGA resources when compared to MPIC without decision feedback. In this letter, FPGA implementation of block parallel DF-MPIC (BP-DF-MPIC) is proposed allowing better tradeoff between performance and FPGA area occupancy. To reach an uncoded bit-error rate of 10−3, BP-DF-MPIC shows a 1.5 dB improvement over the MPIC without decision feedback with only 8% increase in FPGA resources compared to 69% for DF-MPIC

Spreading Code Assignment Strategies for MIMO-CDMA Systems Operating in Frequency-Selective Channels

Code Division Multiple Access (CDMA) and multiple input multiple output- (MIMO-) CDMA systems suffer from multiple access interference (MAI) which limits the spectral efficiency of these systems. By making these systems more power efficient, we can increase the overall spectral efficiency. This can be achieved through the use of improved modulation and coding techniques. Conventional MIMO-CDMA systems use fixed spreading code assignments. By strategically selecting the spreading codes as a function of the data to be transmitted, we can achieve coding gain and introduce additional degrees of freedom in the decision variables at the output of the matched filters. In this paper, we examine the bit error rate performance of parity bit-selected spreading and permutation spreading under different wireless channel conditions. A suboptimal detection technique based on maximum likelihood detection is proposed for these systems operating in frequency selective channels. Simulation results demonstrate that these code assignment techniques provide an improvement in performance in terms of bit error rate (BER) while providing increased spectral efficiency compared to the conventional system. Moreover, the proposed strategies are more robust to channel estimation errors as well as spatial correlation

FPGA Implementation of an MUD Based on Cascade Filters for a WCDMA System

The VLSI architecture targeted on FPGAs of a multiuser detector based on a cascade of adaptive filters for asynchronous WCDMA systems is presented. The algorithm is briefly described. This paper focuses mainly on real-time implementation. Also, it focuses on a design methodology exploiting the modern technology of programmable logic and overcoming the limitations of commercial tools. The dedicated architecture based on a regular structure of processors and a special structure of memory exploiting FPGA architecture maximizes the processing rate. The proposed architecture was validated using synthesized data in UMTS communication scenarios. The performance goal is to maximize the number of users of different WCDMA data traffics. This dedicated architecture can be used as an intellectual property (IP) core processing an MUD function in the system-on-programmable-chip (SOPC) of UMTS systems. The targeted FPGA components are Virtex-II and Virtex-II Pro families of Xilinx.</p

Theoretical Analysis of The r th Best Relay Selection for Amplify-and-Forward Systems

The two-hop relay network is well studied when both hops experience Rayleigh Fading channels. It is also studied when the SNR of one of the hops is the maximum among a set of i.i.d. Rayleigh Fading channels. In this paper, the two-hop relay network is analyzed when the SNR of one of the hops is the r th biggest value among a set of N i.i.d. Rayleigh Fading channels. Also we have analyzed the case when the SNR of the first hop and the second hop are respectively the r th and q th biggest values among their set. The explicit PDF and CDF and also the average error probability for both cases are calculated in closed form. The diversity order of the resulting link is also calculated. The results have several applications in the analysis diversity schemes, especially in the analysis of relay assignment based on max-min criterion