This dissertation is composed of two independent studies: Cellular research and WBAN (Wireless Body Area Network) research. Both investigations are directed towards improving the system performance in wireless communication systems in terms of Quality of Service (QoS) and system capacity. For the Cellular research part, this dissertation will present novel user-specific QoS requirements as defined by their respective Mean Opinion Score (MOS) formulas, and associated schedulers for wireless applications and systems that optimize spectral allocation. User-specific QoS requirements are defined and several methods to make use of such requirements to maximum the spectral utilization are presented. Five User-Specific QoS Aware (USQA) schedulers are proposed that consider the user-specific QoS requirements in the allocation of spectral resources. Schedulers are introduced that dynamically adapt to the user-specific QoS requirements to improve quality as measured by the MOS, or the system capacity, or can improve both the quality and system capacity. Due to the different cell deployment arrangements and inter-cell interference in heterogeneous networks in comparison to homogeneous networks, the USQA scheduling is also analyzed and the system performance is evaluated in such networks. Throughput improvements of File Transfer Protocol (FTP) applications benefiting from the rate adaptation and MAC (Media Access Control) scheduling algorithms for video applications that incorporate user-specific QoS requirements to improve system capacity are demonstrated. Another novel approach recognizes that the user-specific frequency sensitivity can be used to improve capacity. There is considerable variation in the audible range of frequencies that can be perceived by individuals, especially at the high frequency end, which is primarily affected by a gradual decline with age. This can be utilized to improve the system performance by personalizing the VoIP codecs and decreasing the user's source data rate for people from an older age group and thus increase the system capacity. Given the potentially substantial system performance gain resulting from the USQA schedulers, it is critical to analyze their feasibility and complexity in practical LTE (4G cellular) and future wireless systems. From the LTE system perspective, LTE QoS end-to-end signaling procedures are addressed, and corresponding protocol adaptations are analyzed in order to support the USQA schedulers. In addition, the optimal scheduling period is analyzed that trades off between performance gain and implementation complexity. In the WBAN research, MIMO (Multiple Input Multiple Output) in vivo antenna technologies are introduced and are motivated by the high data rate requirements of wirelessly transmitted low-delay High Definition (HD) video during Minimally Invasive Surgery (MIS). MIMO in vivo technologies are proposed to be used in the in vivo environments to enhance and determine the maximum data transmission rate while satisfying the Specific Absorption Rate (SAR) power limitations. Various factors are considered in the MIMO in vivo study including antenna separation, antenna angular positions, human body size, and system bandwidth to determinate the maximum data rate that can be supported.

This dissertation will present several novel techniques that use cooperation and diversity to improve the performance of multihop Wireless Sensor Networks, as measured by throughput, delay, and reliability, beyond what is achievable with conventional error control technology. We will investigate the applicability of these new technologies to Wireless Body Area Networks (WBANs) an important emerging class of wireless sensor networks. WBANs, which promise significant improvement in the reliability of monitoring and treating people's health, comprise a number of sensors and actuators that may either be implanted in vivo or mounted on the surface of the human body, and which are capable of wireless communication to one or more external nodes that are in close proximity to the human body. Our focus in this research is on enhancing the performance of WBANs, especially for emerging real-time in vivo traffic such as streaming real-time video during surgery. Because of the nature of this time-sensitive application, retransmissions may not be possible. Furthermore, achieving minimal energy consumption, with the required level of reliability is critical for the proper functioning of many wireless sensor and body area networks. Additionally, regardless of the traffic characteristics, the techniques we introduce strive to realize reliable wireless sensor networks using (occasionally) unreliable components (wireless sensor nodes). To improve the performance of wireless sensor networks, we introduce a novel technology Cooperative Network Coding, a technology that synergistically integrates the prior art of Network Coding with Cooperative Communications. With the additional goal of further minimizing the energy consumed by the network, another novel technology Cooperative Diversity Coding was introduced and is used to create protection packets at the source node. For representative applications, optimized Cooperative Diversity Coding or Cooperative Network Coding achieves ≥ 25% energy savings compared to the baseline Cooperative Network Coding scheme. Cooperative Diversity Coding requires lees computational complexity at the source node compared to Cooperative Network Coding. To improve the performance and increase the robustness and reliability of WBANs, two efficient feedforward error-control technologies, Cooperative Network Coding (CDC) and Temporal Diversity Coding (TDC), are proposed. Temporal Diversity Coding applies Diversity Coding in time to improve the WBAN's performance. By implementing this novel technique, it is possible to achieve significant improvement (50%) in throughput compared to extant WBANs. An example of an implementation of in vivo real-time application, where TDC can improve the communications performance, is the MARVEL (Miniature Anchored Robotic Videoscope for Expedited Laparoscopy) research platform developed at USF. The MARVEL research platform requires high bit rates (100 Mbps) for high-definition transmission. Orthogonal Frequency Division Multiplexing (OFDM), a widely used technology in fourth generation wireless networks (4G) that achieves high transmission rates over dispersive channels by transmitting serial information through multiple parallel carriers. Combining Diversity Coding with OFDM (DC-OFDM) promises high reliability communications while preserving high transmission rates. Most of the carriers transport original information while the remaining (few) carriers transport diversity coded (protection) information. The impact of DC-OFDM can extend far beyond in vivo video medical devices and other special purpose wireless systems and may find significant application in a broad range of ex vivo wireless systems, such as LTE, 802.11, 802.16.

This dissertation presents several novel accomplishments in the research area of Wireless Body Area Networks (WBANs), including in vivo channel characterization, optimization and game theoretical approaches for energy efficiency in WBANs. First, we performed the in vivo path loss simulations with HFSS human body model, built a phenomenological model for the distance and frequency dependent path loss, and also investigated angle dependent path loss of the in vivo wireless channel. Simulation data is produced in the range of 0.4−6 GHz for frequency, a wide range of distance and different angles. Based on the measurements, we produce mathematical models for in body, on body and out of body regions. The results show that our proposed models fit well with the simulated data. Based on our research, a comparison of in vivo and ex vivo channels is summarized. Next, we proposed two algorithms for energy efficiency optimization in WBANs and evaluated their performance. In the next generation wireless networks, where devices and sensors are heterogeneous and coexist in the same geographical area creating possible collisions and interference to each other, the battery power needs to be efficiently used. The first algorithm, Cross-Layer Optimization for Energy Efficiency (CLOEE), enables us to carry out a cross-layer resource allocation that addresses the rate and reliability trade-off in the PHY, as well as the frame size optimization and transmission efficiency for the MAC layer. The second algorithm, Energy Efficiency Optimization of Channel Access Probabilities (EECAP), studies the case where the nodes access the medium in a probabilistic manner and jointly determines the optimal access probability and payload frame size for each node. These two algorithms address the problem from an optimization perspective and they are both computationally efficient and extensible to 5G/IoT networks. Finally, in order to switch from a centralized method to a distributed optimization method, we study the energy efficiency optimization problem from a game theoretical point of view. We created a game theoretical model for energy efficiency in WBANs and investigated its best response and Nash Equilibrium of the single stage, non-cooperative game. Our results show that cooperation is necessary for efficiency of the entire system. Then we used two approaches, Correlated Equilibrium and Repeated Game, to improve the overall efficiency and enable some level of cooperation in the game.