Multi-antenna transmission and reception (known as MIMO) is widely touted as the key technology for enabling wireless broadband services, whose widespread success will require ten times higher spectral efficiency than current cellular systems, at ten times lower cost per bit. Spectrally efficient, inexpensive cellular systems are by definition densely populated and interference-limited. But spatial multiplexing MIMO systems – whose principal merit is a supposed dramatic increase in spectral efficiency – lose much of their effectiveness in high levels of interference. This paper overviews several approaches for handling interference in multicell MIMO systems. The discussion is applicable to any multi-antenna cellular network including 802.16e/WiMAX, 3GPP (HSDPA and 3GPP LTE) and 3GPP2 (1xEVDO). We argue that many of the traditional interference management techniques have limited usefulness (or are even counterproductive) when viewed in concert with MIMO. The problem of interference in MIMO systems is too large in scope to be handled with a single technique: in practice a combination of complementary countermeasures will be needed. We overview emerging system-level interference-reducing strategies based on cooperation, which will be important for overcoming interference in future spatial multiplexing cellular systems.

Diversity is an intrinsic property of wireless networks. Recent years have witnessed the emergence of many distributed protocols like ExOR, MORE, SOAR, SOFT, and MIXIT that exploit receiver diversity in 802.11-like networks. In contrast, the dual of receiver diversity, sender diversity, has remained largely elusive to such networks. This paper presents SourceSync, a distributed architecture for harnessing sender diversity. SourceSync enables concurrent senders to synchronize their transmissions to symbol boundaries, and cooperate to forward packets at higher data rates than they could have achieved by transmitting separately. The paper shows that SourceSync improves the performance of opportunistic routing protocols. Specifically, SourceSync allows all nodes that overhear a packet in a wireless mesh to simultaneously transmit it to their nexthops, in contrast to existing opportunistic routing protocols that are forced to pick a single forwarder from among the overhearing nodes. Such simultaneous transmission reduces bit errors and improves throughput. The paper also shows that SourceSync increases the throughput of 802.11 last hop diversity protocols by allowing multiple APs to transmit simultaneously to a client, thereby harnessing sender diversity. We have implemented SourceSync on the FPGA of an 802.11-like radio platform. We have also evaluated our system in an indoor wireless testbed, empirically showing its benefits.

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This article addresses our concept for a highly dynamic scenario-based simulation platform for diverse wireless communication circumstance, which provides users high flexibility and ease for use to simulate complex wireless communication scenarios. It is observed that different simulation activities for wireless communication systems usually conduct a very similar processing flow. Due to this similarity the process flows could be segmented and categorized to several common tasks so that these common tasks can be easily re-used to speed up the development of new setups of simulations, such as different environment scenarios, different physical layer (PHY) parameters and even different PHY protocols, etc. However, this kind of segmentation reduces the efficiency of the computation due to the overheads of exchanging data among the tasks. To complement the loss of the computation efficiency, we structured a parallel and distributed simulation (PADS) engine to take advantage of the independence among the tasks and the high parallel computation power of the distributed computing platform (DCP). 1.

There is a singular dichotomy to writing a dissertation: it is an isolated endeavor, yet impossible without the support of family, friends, and colleagues. First of all, I would like to thank my family, for their unconditional love, support, and sacrifices. I would like to thank my father for teaching me the value of patience (with mild success), my mother for teaching me the value of spontaneity (with great success), and my sisters Shachi and Shruti for showering me with love, affection, and attention. They made me the person I am today. I would like to express my deepest gratitude towards my advisor Prof. Brian L. Evans. Prof. Evans has been a constant source of support and ideas; someone to talk to, rather than report to; guiding me to find my path, rather than directing me towards one. His intelligence, breadth of experience, and organizational ability are attributes that I can only hope to duplicate. I would like to thank my committee members Prof. Jeff Andrews, Prof. Robert Heath, Prof. Elmira Popova, and Prof. Haris Vikalo for their prying questions and invaluable comments. I would especially like to thank Prof. Andrews and Prof. Heath, whose classes have been a most enriching experience. I would also like to thank Prof. Surendra Prasad and Prof. Shiv Joshi for inspiring me to pursue signal processing and communications. I would like to thank my best friends from high school: Mayank Sharma, v Dr. Sahil Khera, Neha Sharma, Kabeer Chawla, and Mukund Kumar for showing me a life outside of studies; my best friends from IIT: Varun Agarwal, Chirag