Non-Guard Interval based and Genetic Algorithm Assisted Frequency Domain Equalization for DS-UWB Systems

In this work, a genetic algorithm (GA) based frequency domain equalization (FDE-GA) scheme was proposed for direct sequence ultra wideband (DS-UWB) wireless communication systems. The proposed FDE-GA scheme does not require a guard interval (GI) and the output of the RAKE receiver is used as the input to our GA. The scheme achieved much higher bandwidth efficiency than conventional FDE methods because of the removal of the inter block interference (IBI) within each block before the GA. The FDE-GA receiver was shown to significantly outperform the RAKE receiver and the RAKE-GA receiver proposed in a previous work, in terms of bit error rate (BER) at a similar complexity. An improvement in the mean square error (MSE) was observed from simulation results presented, as a result of increase in the number of pilot symbols.Keywords: frequency domain equalization, guard interval, ultra-wideband, genetic algorithm, inter block-interferenc

Timing and Carrier Synchronization in Wireless Communication Systems: A Survey and Classification of Research in the Last 5 Years

Timing and carrier synchronization is a fundamental requirement for any wireless communication system to work properly. Timing synchronization is the process by which a receiver node determines the correct instants of time at which to sample the incoming signal. Carrier synchronization is the process by which a receiver adapts the frequency and phase of its local carrier oscillator with those of the received signal. In this paper, we survey the literature over the last 5 years (2010–2014) and present a comprehensive literature review and classification of the recent research progress in achieving timing and carrier synchronization in single-input single-output (SISO), multiple-input multiple-output (MIMO), cooperative relaying, and multiuser/multicell interference networks. Considering both single-carrier and multi-carrier communication systems, we survey and categorize the timing and carrier synchronization techniques proposed for the different communication systems focusing on the system model assumptions for synchronization, the synchronization challenges, and the state-of-the-art synchronization solutions and their limitations. Finally, we envision some future research directions

Performance Enhancement of DS-UWB Short Range Communication System Using Equalization Techniques

UWB is a major research area in the field of wireless communication. The IEEE 802.15.3a has been assigned the job of standardizing it. It is being considered as a breakthrough technology capable enough to revolutionize short range wireless communication. Ultra wideband communication as its name implies has large absolute bandwidth greater than 500 MHz and operating frequency band is 3.1 GHz- 10.6GHz. It is a rapidly growing technology that plays a very promising role in modern age wireless communication. It finds application in various sectors, for example in medical application to observe the status of patient using wireless health monitoring of life sustaining systems. In vehicular technology it can be used for obstacle avoidance and fast data transmission, and in military application as radar for detection behind walls and other blockages. Since it is based on short pulse carrier less transmission so hardware implementation becomes less complex and cheap. Thesis work has been done to study the BPSK modulation based DS-UWB communication system. Direct sequence spread spectrum (DSSS) technique along with UWB signal and two types of equalization techniques has been incorporated to mitigate the multipath fading effect associated with S-V indoor channel. Rake receiver has been used to utilize the energy of various delayed multipath components to improve the performance of the system. In short range communication process, indoor channel model or UWB channel model has been studied with different transmitter receiver separation, using some fundamental parameters of channel. Inter symbol interference (ISI) is a major problem in frequency selective fading channels, to overcome this problem, RAKE-MMSE equalizer and single carrier frequency domain equalizer (SC-FDE) have been incorporated. Thesis comprises of the system performance study and design done by using the above said equalization techniques for DS-UWB communications system