“CSMA-Based Link Scheduling in Multihop MIMO Networks using SINR Model ”

The main aim of this study to resolve the problem of distributed scheduling in multi-hop MIMO networks. We will first develop a “MIMO pipe” model which will provide the required SINR , which gives the rate-reliability tradeoff in MIMO communications.Here we are going to study development of CSMA-based MIMO-pipe scheduling especially under the SINR model.We are going to choose the SINR model over the conventionally studied matching or protocol-based interference models because it has ability to capture the impact of interference in wireless networks. Here each node is equipped with an antenna array. In CSMA based scheduling, nodes will first sense the channel activity before attempting transmissions, whenever the channel is sensed to be idle, the nodes will continue with data transmissions. When the channel is detected to be busy, the nodes have to wait for a random amount of backoff time before reattempting the transmission.We will study that protocol model based throughput-optimal CSMA based scheduling, would not work well under the SINR model because its has dynamic and intrinsic link coupling. To tackle this challenge,CSMA-based MIMO-pipe scheduling is develpoed in both discrete-time system and continuous-time system

“CSMA-Based and Optimal link scheduling in Multihop MIMO Networks using SINR Model ”

The development of high-performance distributed scheduling algorithms for multi-hop wireless networks have become a matter of interest in recent years. The problem is challenging when studied under a physical interference model because it requires the SINR to be above a certain threshold at the receiver for decoding success. Under this SINR model, the transmission failure can be caused by interference due to simultaneous transmissions from far away nodes, which intensifies the difficulty in developing a distributed algorithm for link scheduling. In this paper, we are going to propose scheduling algorithm that uses carrier sensing and show that the algorithm is applicable to distributed implementation as well as it results in throughput optimality. This algorithm has a feature called the dual-state approach. It separates the transmission schedules from the system state means control state ans data state are separated hence can be shown to improve delay performance

Link Scheduling Algorithms For In-Band Full-Duplex Wireless Networks

In the last two decades, wireless networks and their corresponding data traffic have grown significantly. This is because wireless networks have become an indispens- able and critical communication infrastructure in a modern society. An on-going challenge in communication systems is meeting the continuous increase in traffic de- mands. This is driven by the proliferation of electronic devices such as smartphones with a WiFi interface along with their bandwidth intensive applications. Moreover, in the near future, sensor devices that form the Internet of Things (IoTs) ecosystem will also add to future traffic growth. One promising approach to meet growing traffic demands is to equip nodes with an In-band-Full-Duplex (IBFD) radio. This radio thus allows nodes to transmit and receive data concurrently over the same frequency band. Another approach to in- crease network or link capacity is to exploit the benefits of Multiple-Input-Multiple- Output (MIMO) technologies; namely, (i) spatial diversity gain, which improves Signal-to-Noise Ratio (SNR) and thus has a direct impact on the data rate used by nodes, and (ii) spatial multiplexing gain, whereby nodes are able to form concurrent links to neighbors

Cross-layer schemes for performance optimization in wireless networks

Wireless networks are undergoing rapid progress and inspiring numerous applications. As the application of wireless networks becomes broader, they are expected to not only provide ubiquitous connectivity, but also support end users with certain service guarantees. End-to-end delay is an important Quality of Service (QoS) metric in multihop wireless networks. This dissertation addresses how to minimize end-to-end delay through joint optimization of network layer routing and link layer scheduling. Two cross-layer schemes, a loosely coupled cross-layer scheme and a tightly coupled cross-layer scheme, are proposed. The two cross-layer schemes involve interference modeling in multihop wireless networks with omnidirectional antenna. In addition, based on the interference model, multicast schedules are optimized to minimize the total end-to-end delay. Throughput is another important QoS metric in wireless networks. This dissertation addresses how to leverage the spatial multiplexing function of MIMO links to improve wireless network throughput. Wireless interference modeling of a half-duplex MIMO node is presented. Based on the interference model, routing, spatial multiplexing, and scheduling are jointly considered in one optimization model. The throughput optimization problem is first addressed in constant bit rate networks and then in variable bit rate networks. In a variable data rate network, transmitters can use adaptive coding and modulation schemes to change their data rates so that the data rates are supported by the Signal to Noise and Interference Ratio (SINR). The problem of achieving maximum throughput in a millimeter-wave wireless personal area network is studied --Abstract, page iv