Multi-User Detection Techniques for DS-CDMA UWB System

2011 ◽  
Vol 204-210 ◽  
pp. 872-878
Author(s):  
Nan Ping Liu ◽  
Xiang Bo Song ◽  
Ke Wen Xia ◽  
Yuan Shi
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Communication Systems ◽  
New Technologies ◽  
Detection Algorithm ◽  
Detection Performance ◽  
Ultra Wideband ◽  
Decision Threshold ◽  
Correct Decision ◽  
Detection Techniques

Ultra-wideband(UWB) is currently one of three new technologies of wireless communication. Multi-user detection technique is mainly used to eliminate multiple access interference（MAI）in DS-CDMA UWB communication systems. Linear multi-user detection algorithm for multi-access interference suppression or even elimination has certain results. But for a fixed decision threshold is set to 0, the detection performance of linear multi-user detection algorithm will be decreased significantly. Therefore a kind of multi-user detection with pre-processing has been researched. Through the pre-processing, we set dynamic threshold to direct decision the user's data bit information so as to solve the problem the linear multi-user detector’s decision threshold which is fixed impact the detection performance. We may get the global optimal solution though pre-processing of using the thought of the branch and bound algorithm and forcing rules. Then the original problem changes into a smaller multi-user detection problem, in order to get the aim of reducing MAI, increasing the probability of a correct decision and reducing the bit error rate. From the simulation experiment results, it is shown that it has a significant effect in system detection, because after pre-processing the probability of a correct decision has increased, and the bit error rate has been reduced.

scholarly journals Multi-hope relay based high capacity energy efficient model for ultra wideband communication system

2017 ◽  
Vol 7 (1.5) ◽  
pp. 118
Author(s):  
B. Rajanna ◽  
P. Chandrashrkar ◽  
K. KishanRao
Keyword(s):  
Spectral Density ◽  
Bit Error Rate ◽  
Error Rate ◽  
Communication Systems ◽  
High Capacity ◽  
Ultra Wideband ◽  
Green Communication ◽  
Coverage Area ◽  
Data Rates ◽  
Ultra Wideband Communication

Demanding large bandwidth and signal robustness over a short distance, ultra wideband communication systems plays an important role. UWB systems exhibits very low spectral density, implies that the interference to narrowband systems is very small. The relay based communication has the advantages of coverage extension, range extension, increase data rates and green communication. The relay based communication with UWB frequency is used to increase the coverage area by using of relays and increasing the data rates by increasing SNR of the links using multi-hop communication. In this paper, capacity and bit error rate of relay based UWB system for indoor and outdoor channel models are analyzed. key Terms—UWB, green communication, multi-hop, capacity, bit error rate, spectral density.

scholarly journals Experimental Implementation and Theoretical Investigation of a Vanadium Dioxide Optical Filter for Bit Error Rate Enhancement of Enhanced Space Shift Keying Visible Light Communication Systems

Computation ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 30 ◽  
Author(s):  
Dimitra K. Manousou ◽  
Argyris N. Stassinakis ◽  
Emmanuel Syskakis ◽  
Hector E. Nistazakis ◽  
Spiros Gardelis ◽  
...  
Keyword(s):  
Visible Light ◽  
Bit Error Rate ◽  
Error Rate ◽  
Vanadium Dioxide ◽  
Background Noise ◽  
Communication Systems ◽  
Optical Filter ◽  
Optical Filters ◽  
Visible Light Communication ◽  
Performance Estimation

Visible Light Communication (VLC) systems use light-emitting diode (LED) technology to provide high-capacity optical links. The advantages they offer, such as the high data rate and the low installation and operational cost, have identified them as a significant solution for modern networks. However, such systems are vulnerable to various exogenous factors, with the background sunlight noise having the greatest impact. In order to reduce the negative influence of the background noise effect, optical filters can be used. In this work, for the first time, a low-cost optical vanadium dioxide (VO2) optical filter has been designed and experimentally implemented based on the requirements of typical and realistic VLC systems in order to significantly increase their performance by reducing the transmittance of background noise. The functionality of the specific filter is investigated by means of its bit error rate (BER) performance estimation, taking into account its experimentally measured characteristics. Numerous results are provided in order to prove the significant performance enhancement of the VLC systems which, as it is shown, reaches almost six orders of magnitude in some cases, using the specific experimental optical filter.

scholarly journals Performance enhancement of MIMO detectors using wavelet de-noising filters

2016 ◽  
Vol 5 (4) ◽  
pp. 131
Author(s):  
Reham Wgeeh ◽  
Amr Hussein ◽  
Mahmoud Attia
Keyword(s):  
Error Rate ◽  
Communication Systems ◽  
Performance Enhancement ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Symbol Error Rate ◽  
Antenna Element ◽  
Detection Techniques ◽  
Information Signal ◽  
Input Multiple Output

Multiple-Input Multiple-Output (MIMO) technology has attracted great attention in many wireless communication systems. It provides significant enhancement in the spectral efficiency, throughput, and link reliability. There are numerous MIMO signal detection techniques that have been studied in the previous decades such as Maximum Likelihood (ML), Zero Forcing (ZF), Minimum Mean Square Error (MMSE) detectors, etc. It is well known that the additive and multiplicative noise in the information signal can significantly degrade the performance of MIMO detectors. During the last few years, the noise problem has been the focus of much research, and its solution could lead to profound improvements in symbol error rate performance of the MIMO detectors. In this paper, ML, ZF, and MMSE based wavelet de-noising detectors are proposed. In these techniques, the noise contaminated signals from each receiving antenna element are de-noised individually in parallel to boost the SNR of each branch. The de-noised signals are applied directly to the desired signal detector. The simulation results revealed that the proposed detectors constructed on de-noising basis achieve better symbol error rate (SER) performance than that of systems currently in use.

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