61 research outputs found
High speed 802.11ad wireless video streaming
The aim of this thesis is to investigate, both theoretically and experimentally, the capability of the IEEE 802.11ad device, the Wireless Gigabit Alliance known as WiGig operating in the 60 GHz band to handle rise in data traffic ubiquitous to high speed data transmission such as bulk data transfer, and wireless video streaming.
According to Cisco and others, it is estimated that in 2020, internet video traffic will account for 82 % of all consumer internet traffic. This research evalu- ated the feasibility of the 60 GHz to provide minimum data rate of about 970 Mbps from the Ethernet link limited or clamped to 1 Gbps. This translated to 97 % effi- ciency with respect to the IEEE 802.11ad system performance. For the first time, the author proposed the enhancement of millimetre wave propagation through the use of specular reflection in non-line-of-sight environment, providing at least 94 % bandwidth utilization. Additional investigations result of the IEEE 802.11ad device in real live streaming of 4k ultra-high definition (UHD) video shows the feasibility of aggressive frequency reuse in the absence of co-channel interference. Moreover, using heuristic approach, this work compared materials absorption and signal reception at 60 GHz and the results gives better performance in contrast to the theoretical values.
Finally, this thesis proposes a framework for the 802.11ad wireless H.264 video streaming over 60 GHz band. The work describes the potential and efficiency of WiGig device in streaming high definition (HD) video with high temporal index (TI) and 4k UHD video with no retransmission. Caching point established at the re-transmitter increase coverage and cache multimedia data. The results in this thesis shows the growing potential of millimeter wave technology, the WiGig for very high speed bulk data transfer, and live streaming video transmission
Optimized Live 4K Video Multicast
4K videos are becoming increasingly popular. However, despite advances in
wireless technology, streaming 4K videos over mmWave to multiple users is
facing significant challenges arising from directional communication,
unpredictable channel fluctuation and high bandwidth requirements. This paper
develops a novel 4K layered video multicast system. We (i) develop a video
quality model for layered video coding, (ii) optimize resource allocation,
scheduling, and beamforming based on the channel conditions of different users,
and (iii) put forward a streaming strategy that uses fountain code to avoid
redundancy across multicast groups and a Leaky-Bucket-based congestion control.
We realize an end-to-end system on commodity-off-the-shelf (COTS) WiGig
devices. We demonstrate the effectiveness of our system with extensive testbed
experiments and emulation
Improving the Performance of Wireless LANs
This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids
Energy-aware adaptive solutions for multimedia delivery to wireless devices
The functionality of smart mobile devices is improving rapidly but these devices are limited
in terms of practical use because of battery-life. This situation cannot be remedied by simply
installing batteries with higher capacities in the devices. There are strict limitations in the
design of a smartphone, in terms of physical space, that prohibit this “quick-fix” from being
possible. The solution instead lies with the creation of an intelligent, dynamic mechanism for
utilizing the hardware components on a device in an energy-efficient manner, while also
maintaining the Quality of Service (QoS) requirements of the applications running on the
device.
This thesis proposes the following Energy-aware Adaptive Solutions (EASE):
1. BaSe-AMy: the Battery and Stream-aware Adaptive Multimedia Delivery (BaSe-AMy)
algorithm assesses battery-life, network characteristics, video-stream properties and
device hardware information, in order to dynamically reduce the power consumption of
the device while streaming video. The algorithm computes the most efficient strategy for
altering the characteristics of the stream, the playback of the video, and the hardware
utilization of the device, dynamically, while meeting application’s QoS requirements.
2. PowerHop: an algorithm which assesses network conditions, device power consumption,
neighboring node devices and QoS requirements to decide whether to adapt the
transmission power or the number of hops that a device uses for communication.
PowerHop’s ability to dynamically reduce the transmission power of the device’s
Wireless Network Interface Card (WNIC) provides scope for reducing the power
consumption of the device. In this case shorter transmission distances with multiple hops
can be utilized to maintain network range.
3. A comprehensive survey of adaptive energy optimizations in multimedia-centric wireless
devices is also provided.
Additional contributions:
1. A custom video comparison tool was developed to facilitate objective assessment of
streamed videos.
2. A new solution for high-accuracy mobile power logging was designed and implemented
Belaidžio ryšio tinklų terpės prieigos valdymo tyrimas
Over the years, consumer requirements for Quality of Service (QoS) has been growing exponentially. Recently, the ratification process of newly IEEE 802.11ad amendment to IEEE 802.11 was finished. The IEEE 802.11ad is the newly con-sumer wireless communication approach, which will gain high spot on the 5G evolution. Major players in wireless market, such as Qualcomm already are inte-grating solutions from unlicensed band, like IEEE 802.11ac, IEEE 802.11ad into their architecture of LTE PRO (the next evolutionary step for 5G networking) (Qualcomm 2013; Parker et al. 2015). As the demand is growing both in enter-prise wireless networking and home consumer markets. Consumers started to no-tice the performance degradation due to overcrowded unlicensed bands. The un-licensed bands such as 2.4 GHz, 5 GHz are widely used for up-to-date IEEE 802.11n/ac technologies with upcoming IEEE 802.11ax. However, overusage of the available frequency leads to severe interference issue and consequences in to-tal system performance degradation, currently existing wireless medium access method can not sustain the increasing intereference and thus wireless needs a new methods of wireless medium access. The main focal point of this dissertation is to improve wireless performance in dense wireless networks. In dissertation both the conceptual and multi-band wireless medium access methods are considered both from theoretical point of view and experimental usage.
The introduction chapter presents the investigated problem and it’s objects of research as well as importance of dissertation and it’s scientific novelty in the unlicensed wireless field.
Chapter 1 revises used literature. Existing and up-to-date state-of-the-art so-lution are reviewed, evaluated and key point advantages and disadvantages are analyzed. Conclusions are drawn at the end of the chapter.
Chapter 2 describes theoretical analysis of wireless medium access protocols and the new wireless medium access method. During analysis theoretical simula-tions are performed. Conclusions are drawn at the end of the chapter.
Chapter 3 is focused on the experimental components evaluation for multi-band system, which would be in line with theoretical concept investigations. The experimental results, showed that components of multi-band system can gain sig-nificant performance increase when compared to the existing IEEE 802.11n/ac wireless systems.
General conclusions are drawn after analysis of measurement results
Recommended from our members
High Performance Local Oscillator Design for Next Generation Wireless Communication
Local Oscillator (LO) is an essential building block in modern wireless radios. In modern wireless radios, LO often serves as a reference of the carrier signal to modulate or demod- ulate the outgoing or incoming data. The LO signal should be a clean and stable source, such that the frequency or timing information of the carrier reference can be well-defined. However, as radio architecture evolves, the importance of LO path design has become much more important than before. Of late, many radio architecture innovations have exploited sophisticated LO generation schemes to meet the ever-increasing demands of wireless radio performances.
The focus of this thesis is to address challenges in the LO path design for next-generation high performance wireless radios. These challenges include (1) Congested spectrum at low radio frequency (RF) below 5GHz (2) Continuing miniaturization of integrated wireless radio, and (3) Fiber-fast (>10Gb/s) mm-wave wireless communication.
The thesis begins with a brief introduction of the aforementioned challenges followed by a discussion of the opportunities projected to overcome these challenges.
To address the challenge of congested spectrum at frequency below 5GHz, novel ra- dio architectures such as cognitive radio, software-defined radio, and full-duplex radio have drawn significant research interest. Cognitive radio is a radio architecture that opportunisti- cally utilize the unused spectrum in an environment to maximize spectrum usage efficiency. Energy-efficient spectrum sensing is the key to implementing cognitive radio. To enable energy-efficient spectrum sensing, a fast-hopping frequency synthesizer is an essential build- ing block to swiftly sweep the carrier frequency of the radio across the available spectrum. Chapter 2 of this thesis further highlights the challenges and trade-offs of the current LO gen-
eration scheme for possible use in sweeping LO-based spectrum analysis. It follows by intro- duction of the proposed fast-hopping LO architecture, its implementation and measurement results of the validated prototype. Chapter 3 proposes an embedded phase-shifting LO-path design for wideband RF self-interference cancellation for full-duplex radio. It demonstrates a synergistic design between the LO path and signal to perform self-interference cancellation.
To address the challenge of continuing miniaturization of integrated wireless radio, ring oscillator-based frequency synthesizer is an attractive candidate due to its compactness. Chapter 4 discussed the difficulty associated with implementing a Phase-Locked Loop (PLL) with ultra-small form-factor. It further proposes the concept sub-sampling PLL with time- based loop filter to address these challenges. A 65nm CMOS prototype and its measurement result are presented for validation of the concept.
In shifting from RF to mm-wave frequencies, the performance of wireless communication links is boosted by significant bandwidth and data-rate expansion. However, the demand for data-rate improvement is out-pacing the innovation of radio architectures. A >10Gb/s mm-wave wireless communication at 60GHz is required by emerging applications such as virtual-reality (VR) headsets, inter-rack data transmission at data center, and Ultra-High- Definition (UHD) TV home entertainment systems. Channel-bonding is considered to be a promising technique for achieving >10Gb/s wireless communication at 60GHz. Chapter 5 discusses the fundamental radio implementation challenges associated with channel-bonding for 60GHz wireless communication and the pros and cons of prior arts that attempted to address these challenges. It is followed by a discussion of the proposed 60GHz channel- bonding receiver, which utilizes only a single PLL and enables both contiguous and non- contiguous channel-bonding schemes.
Finally, Chapter 6 presents the conclusion of this thesis
Remote Control of Unmanned Aerial Vehicles Through the Internet and IEEE 802.11
This dissertation focuses on real-time control of Unmanned Aerial Vehicles (UAVs) through TCP/IP/IEEE 802.11. Using the MAVLink protocol - an open-source protocol for micro air vehicles - a solution that allows the exchange, in real-time, of control messages between a UAV and a remote Control Station was implemented. In order to allow the UAV control by a remote user, the vehicle streams a real-time video feed captured by a video-camera on board. The main challenge of this dissertation is related about the designing and implementation of a fast handover solution that allows an uninterruptible communication
Cooperative systems based signal processing techniques with applications to three-dimensional video transmission
Three-dimensional (3-D) video has recently emerged to offer an immersive multimedia experience that can not be offered by two-dimensional (2-D) video applications. Currently, both industry and academia are focused on delivering 3-D video services to wireless communication systems. Modern video communication systems currently adopt cooperative communication and orthogonal frequency division multiplexing (OFDM) as they are an attractive solution to combat fading in wireless communication systems and achieve high data-rates. However, this strong motivation to transmit the video signals over wireless systems faces many
challenges. These are mainly channel bandwidth limitations, variations of signal-to-noise ratio
(SNR) in wireless channels, and the impairments in the physical layer such as time varying phase noise (PHN), and carrier frequency offset (CFO). In response to these challenges, this thesis seeks to develop efficient 3-D video transmission methods and signal processing algorithms that can overcome the effects of error-prone wireless channels and impairments in the physical layer.
In the first part of the thesis, an efficient unequal error protection (UEP) scheme, called video packet partitioning, and a new 3-D video transceiver structure are proposed. The proposed video transceiver uses switching operations between various UEP schemes based on the packet partitioning to achieve a trade- off between system complexity and performance. Experimental results show that
the proposed system achieves significantly high video quality at different SNRs with the lowest possible bandwidth and system complexity compared to direct transmission schemes.
The second part of the thesis proposes a new approach to joint source-channel coding (JSCC) that simultaneously assigns source code rates, the number of high and low priority packets, and channel code rates for the application, network, and physical layers, respectively. The proposed JSCC algorithm takes into account the rate budget constraint and the available instantaneous SNR of the best relay selection in cooperative systems. Experimental results show that the proposed JSCC algorithm outperforms existing algorithms in terms of peak signal-to-noise ratio (PSNR).
In the third part of the thesis, a computationally efficient training based approach for joint channel, CFO, and PHN estimation in OFDM systems is pro- posed. The proposed estimator is based on an expectation conditional maximization (ECM) algorithm. To compare the
estimation accuracy of the proposed estimator, the hybrid Cram´er-Rao lower bound (HCRB) of hybrid parameters of interest is derived. Next, to detect the signal in the presence of PHN, an iterative receiver based on the extended Kalman filter (EKF) for joint data detection and PHN mitigation is proposed. It is demonstrated by numerical simulations that, compared to existing algorithms, the
performance of the proposed ECM-based estimator in terms of the mean square error (MSE) is closer to the derived HCRB and outperforms the existing estimation algorithms at moderate-to-high SNRs. Finally, this study extends the research on joint channel, PHN, and CFO estimation one step
forward from OFDM systems to cooperative OFDM systems. An iterative algorithm based on the ECM in cooperative OFDM networks in the presence of unknown channel gains, PHNs and CFOs is applied. Moreover, the HCRB for the joint estimation problem in both decode-and-forward (DF) and
amplify-and-forward (AF) relay systems is presented. An iterative algorithm based on the EKF for data detection and tracking the unknown time-varying PHN throughout the OFDM data packet is also used. For more efficient 3-D video transmission, the estimation algorithms and UEP schemes based packet portioning were combined to achieve a more robust video bit stream in the presence of PHNs. Applying this combination, simulation results demonstrate that promising bit-error-rate (BER) and PSNR performance can be achieved at the destination at different SNRs and PHN variance.
The proposed schemes and algorithms offer solutions for existing problems in the techniques for applications to 3-D video transmission
- …