IoT services and many more evolving applications. Obviously, the most attractive part of such human and machine interface has revolutionized the network access strategies and allows complete mobility to an end user at his convenience even at a competitive cost. These technological improvements always need a thorough understanding and deepening of the related scientific and engineering research. The main focus of the modern researchers has been to enhance the usage of the available spectrum, bandwidth efficiency and wireless link performances, which leads to exploring new engineering solutions.

This issue contains four articles emphasizing the engineering aspects and techniques to achieve higher data rate in the given bandwidth and also to improve the link connectivity performance in the wireless faded environment. The first three papers have presented appropriate spectrum utilization and optimum channel utilization technologies, followed by a review of image processing in the fourth paper.

The first paper, "Planning TV White Space Network for Broadband Services for a Rural South-East Nigerian Community", by A N Osakwe, G O Uzedhe and D U Onyishi, describes issues related to the usage of TV White Space (TVWS) for secondary application in a rural area of South-East Nigeria for broadband internet applications. The network architecture for the proposed system has been modeled using the existing communication infrastructure. The paper discusses many emerging initiatives to reallocate the unused spectrum to the needy areas for enhanced spectrum utilization.

The inclusion of MIMO in the IMAX system provides a robust platform to resolve the channel impairment caused by space, time and frequency selective fading conditions. The suitable diversity scheme implementation increases the data rate and system performance in a faded environment. The second paper, "MIMO-WIMAX Channel MATLAB Simulation Using Alamouti and OSTBC Code", by Sonal Rohit and Preeti Trivedi, presents Bit Error Rate (BER) analysis for image data using the MIMO system with finite-bit feedback approach in QAM modulation technique. The paper reports the performance analysis of the MIMO-WIMAX system using different modulation schemes under channel conditions like AWGN for Alamouti and OSTBC. The findings of the considered modulation formats confirm a significant diversity gain in the considered wireless environment.

Phased Array Antenna (PAA) system reinforces the radiation pattern in a desired direction to improve the SNR at the receiver. The third paper, "Series Feed Microstrip Antenna Array for RADAR Systems", by Kanchan H Wagh and Shashank S Shriramwar, investigates the microstrip antenna array towards its resonance frequency characterization on the considered array configuration with appropriate feeding techniques. The paper finds an improvement in the performance by series feed taper structure but with a compromise of lower bandwidth. The last paper, "Feature Extraction and Classification Techniques for Brain Tumour Images: A Review", by Sowjanya Velugubantla and Sasibhushana Rao Gottapu, reviews the image processing technique used to detect brain tumors, classifying them into preprocessing, feature extraction and other classification categories. These methods are very useful to classify the benign and malignant tumors of brain and are crucial in extracting the hidden information of the image for appropriate action.