Performance Analysis of Binary Sensor-Based Cooperative Diversity Using Limited Feedback

Communications engineering / telecommunication

Chapter Performance Analysis of Binary Sensor-Based Cooperative Diversity Using Limited Feedback

Communications engineering / telecommunication

RECEIVED SNR BASED CODE AND ANTENNA/RELAY SELECTION FOR LIMITED FEEDBACK COMMUNICATION

Sınırlı geribeslemeli çok-girdili çok-çıktılı (ÇGÇÇ) haberleşme sisteminde kod seçimi ve verici anten seçimi yaygın olarak kullanılır. Eğer vericideki bir antenin kanal kazancı diğer antenlerin kanal kazançlarına göre çok büyükse verici anten seçimi kullanmak alıcıdaki Sinyalin Gürültüye Oranı (SGO)'nı artırır. Buna karşılık, vericideki antenlerin kanal kazançları birbirlerine yakın değerlerde ise kod seçimi kullanmak alıcıdaki SGO'yu arttırır. Bu makalede, ÇGÇÇ haberleşmesinde alıcıdaki SGO'yu arttırmak için uyarlamalı kod ve anten seçimi önerilmiştir. Bu teknikte, fazladan bir bitlik geribesleme kullanılarak verici anten seçimine ve kod seçimine göre alıcıda daha iyi bir SGO değeri elde edilir. Detaylı benzetimler göstermiştir ki, üç verici anten için uyarlamalı kod ve anten seçiminde kullanılacak 4 bitlik geribesleme, kod seçimi olarak kullanılan genişletilmiş dengeli uzay-zaman blok kodlamanın ideal geribesleme başarımını elde etmektedir. İdeal geribesleme ise kanal durum bilgisinin vericide tam olarak bilinmesini gerektirir. Ayrıca, önerilen teknik işbirlikli haberleşmeye uygulanmış ve benzer başarım artışı sağlanmıştır. Önerilen tekniğin ÇGÇÇ ile işbirlikli haberleşmesine uygulanmasındaki fark, anten seçimi yerine röle seçiminin yapılmasıdır. Code selection and transmit antenna selection are widely used in limited feedback multi input multi output (MIMO) communication system. When one of the antenna channel gains is much higher than the other antenna channel gains; using antenna selection method increases received Signal-to-Noise Ratio (SNR) at the receiver. However, when antenna channel gains are close to each other; using code selection method increases the received SNR at the receiver. In this paper, we propose an adaptive code and antenna selection scheme to increase the received SNR at the destination for MIMO system. In this technique, using one additional feedback bit yields improved SNR at the destination compared to using solely code or transmit antenna selection method. Detailed simulations show that adaptive code and antenna selection with four bit feedback yields a performance of the extended balanced space-time block coding with ideal feedback which requires exact channel state information at the transmitter. In addition, the proposed technique is applied into the cooperative communication and similar performance improvement is observed. The difference between MIMO and cooperative communication is using relay selection instead of antenna selection

Smart Wireless Sensor Networks

The recent development of communication and sensor technology results in the growth of a new attractive and challenging area - wireless sensor networks (WSNs). A wireless sensor network which consists of a large number of sensor nodes is deployed in environmental fields to serve various applications. Facilitated with the ability of wireless communication and intelligent computation, these nodes become smart sensors which do not only perceive ambient physical parameters but also be able to process information, cooperate with each other and self-organize into the network. These new features assist the sensor nodes as well as the network to operate more efficiently in terms of both data acquisition and energy consumption. Special purposes of the applications require design and operation of WSNs different from conventional networks such as the internet. The network design must take into account of the objectives of specific applications. The nature of deployed environment must be considered. The limited of sensor nodes� resources such as memory, computational ability, communication bandwidth and energy source are the challenges in network design. A smart wireless sensor network must be able to deal with these constraints as well as to guarantee the connectivity, coverage, reliability and security of network's operation for a maximized lifetime. This book discusses various aspects of designing such smart wireless sensor networks. Main topics includes: design methodologies, network protocols and algorithms, quality of service management, coverage optimization, time synchronization and security techniques for sensor networks