Browsing by Author "Al-Akaidi, Marwan, 1959-"
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Item Open Access Adaptive unicast video streaming with rateless codes and feedback.(IEEE, 2010-02) Ahmad, Shakeel; Hamzaoui, Raouf; Al-Akaidi, Marwan, 1959-Video streaming over the Internet and packet-based wireless networks is sensitive to packet loss, which can severely damage the quality of the received video. To protect the transmitted video data against packet loss, application-layer forward error correction (FEC) is commonly used. Typically, for a given source block, the channel code rate is fixed in advance according to an estimation of the packet loss rate. However, since network conditions are difficult to predict, determining the right amount of redundancy introduced by the channel encoder is not obvious. To address this problem, we consider a general framework where the sender applies rateless erasure coding to every source block and keeps on transmitting the encoded symbols until it receives an acknowledgment from the receiver indicating that the block was decoded successfully. Within this framework, we design transmission strategies that aim at minimizing the expected bandwidth usage while ensuring successful decoding subject to an upper bound on the packet loss rate. In real simulations over the Internet, our solution outperformed standard FEC and hybrid ARQ approaches. For the QCIF Foreman sequence compressed with the H.264 video coder, the gain in average peak signal to noise ratio over the best previous scheme exceeded 3.5 decibels at 90 kilobits per second.Item Metadata only Automatic production of quantisation matrices based on perceptual modelling of wavelet coefficients for grey scale images.(Elsevier, 2010-04) Al-Hudhud, Ghada; Ibrahim, M. K.; Al-Akaidi, Marwan, 1959-Item Metadata only A distributive algorithm for WLAN localization.(IEEE, 2010) Khan, A. U.; Al-Akaidi, Marwan, 1959-Item Metadata only An efficient negative acknowledgement-based transport protocol in 802.11 media streaming(Inderscience Publishers, 2014) Suherman; Al-Akaidi, Marwan, 1959-Item Open Access Error resilient packet-switched video telephony with adaptive rateless coding and reference picture selection.(EUROSIS, 2010-12) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-Providing high-quality video for packet-switched wireless video telephony on hand-held devices is a challenging task due to packet loss, limited available bandwidth, and complexity constraints. We propose a low-complexity channel-adaptive error resilience technique that combines application-layer forward error correction (FEC) with rateless codes, retransmission, and reference picture selection. Experimental results for H.264 video sequences show that the proposed technique achieves significant peak-signal-to-noise ratio (PSNR) and percentage degraded video duration (PDVD) improvements over previous techniques in networks involving two wireless links.Item Open Access Error-resilient packet switched H.264 mobile video telephony with LT coding and reference picture selection.(EURASIP, 2009-08) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-Packet switched video telephony over wireless networks for hand-held devices requires low-delay, low-complexity error control mechanisms to deal with packet loss. We present an efficient solution for 3G networks based on LT coding, reference picture selection, and cross-layer optimization. Experimental results on a 3G network simulator for H.264 compressed standard video sequences show that our method achieves significant peak-signal-to-noise ratio and percentage degraded video duration improvements over a state of the art technique.Item Metadata only Error-resilient packet-switched mobile video telephony with channel-adaptive rateless coding and early reference picture selection(Springer, 2016-02) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-Providing high-quality video for packet-switched wireless video telephony on handheld devices is a challenging task due to packet loss, varying bandwidth, and end-to-end delay constraints. While many error resilience techniques have been proposed for video transmission over wireless channels, only a few were specifically designed for mobile video telephony. We propose a low-complexity channel-adaptive error resilience technique for packet-switched mobile video telephony, which combines rateless coding, feedback, and reference picture selection. In contrast to previous approaches, our technique uses cumulative feedback at every transmission opportunity and predicts when decoding is likely to fail so that reference picture selection can be triggered at an early stage. Experimental results for H.264 video sequences show that the proposed technique can achieve improvements of 1.64 dB in peak signal-to-noise ratio over benchmark techniques in simulated Long-Term Evolution networks.Item Metadata only High-performance scalable bidirectional mixed radix-2n serial-serial multipliers(IET, 2007-09-01) Almiladi, A.; Ibrahim, M. K.; Al-Akaidi, Marwan, 1959-; Aggoun, A.Two new high-performance bidirectional mixed radix-2n serial-serial multipliers are presented. The new designs have improved the area-time performance by ~31% when compared with existing radix-2n serial-serial multipliers. The second design is the first twin-pipe bidirectional radix-2n serial-serial multiplier reported in the literature. The twin-pipe multiplier can be used to perform two successive K-digit multiplications in 2K + 6 cycles without truncating the results. As a consequence, new data can be fed into the multiplier every K+3 cycles. Both proposed designs possess the scalability feature that is missing in existing radix-2n serial-serial multipliers because of the storage elements, which depend on the number of digits needed at the front-end to ensure correct functionality. As a final remark, another significant aspect of the proposed mixed radix-2n serial-serial architecture and its twin-pipe version is that they can be pipelined to the bit-level and give the designer the flexibility to obtain the best trade-off between throughput rate and hardware cost by varying the digit size and the number of pipelining levels.Item Open Access Inter-frame retransmission for video surveillance over WIMAX(EUROSIS, 2011-11) Suherman; Al-Akaidi, Marwan, 1959-; Hamzaoui, RaoufVideo surveillance is an important application for activity and security monitoring. Surveillance application can take advantage of wireless infrastructure which provides installation flexibility and terminal mobility. However, wireless video transmission is prone to interferences which degrade video quality. This paper proposes an inter-frame retransmission protocol for video surveillance over WiMAX. The protocol reduces packet and frame delay compared to existing protocols.Item Metadata only Link stability and mobility in ad hoc networks(Institute of Engineering and Technology, 2007-04-01) Al-Akaidi, Marwan, 1959-; Alchaita, Mohammed HuseinThe fact that ad hoc networks are required to support mobility of individual network nodes results in problems arising when routing data. These problems include route loss, poor longevity of established routes and asymmetric communications links. Mobility of nodes also increases the control traffic overhead and affects the performance of the protocol. Mobility can, however, be exploited to improve route longevity when establishing the route. In some situations, the source of information is not available (e.g. GPS information in the underground), hence protocols relying on this information will fail to operate correctly. In such situations, alternative `self-content' information should be available to perform the needed task of routing. Three novel schemes that make use of such information, the heading direction angle, to provide a mechanism for establishing and maintaining robust and long-lived routes are presented. The results show that these schemes reduce the overhead and increase the route longevity when compared with the AODV protocol. The schemes described can operate as a standalone mechanism or can be adopted by other routing protocols in order to improve their performance.Item Metadata only MIMO-OFDM-based DVB-H systems: a hardware design for a PAPR reduction technique(IEEE, 2006-11-01) Al-Akaidi, Marwan, 1959-; Gow, J. A.; Daoud, O.Digital video broadcasting - handheld (DVB-H) is the technology driving mobile TV, which uses orthogonal frequency division multiplexing (OFDM) systems with multiple-input multiple-output technology (MIMO). These mobile communication systems have a promising future of supporting high data rate transmissions for both video and data. However, since the OFDM systems are sensitive to the peak-to-average power ratio (PAPR) problem, this work proposes a new technique (novel technique to reduce the PAPR based on turbo coding (NTRPT)), based on the turbo encoding technology, to reduce the PAPR effects for MIMO-OFDM-based DVB-H systems. This technique has been implemented and validated in hardware. It can support different types of modulation and coding techniques, and offers better results in reducing the PAPR than the conventional techniques currently proposed for this purpose, such as the clipping technique and the partial transmit sequence (PTS) technique, presented here using computer simulations.Item Metadata only Minimizing line energy loss of radial distribution feeder with a PV Distributed Generation unit avoiding reverse power flow(IEEE, 2011) Al-Sabounchi, Ammar M. Munir; Gow, J. A.; Al-Akaidi, Marwan, 1959-; Al-Thani, H.Item Open Access Optimal packet loss protection of progressively compressed 3D meshes(IEEE, 2009-11) Ahmad, Shakeel; Hamzaoui, Raouf; Al-Akaidi, Marwan, 1959-We consider a state of the art system that uses layered source coding and forward error correction with Reed- Solomon codes to efficiently transmit 3D meshes over lossy packet networks. Given a transmission bit budget, the performance of this system can be optimized by determining how many layers should be sent, how each layer should be packetized, and how many parity bits should be allocated to each layer such that the expected distortion at the receiver is minimum. The previous solution for this optimization problem uses exhaustive search, which is not feasible when the transmission bit budget is large.We propose instead an exact algorithm that solves this optimization problem in linear time and space. We illustrate the advantages of our approach by providing experimental results for the CPM (Compressed Progressive Meshes) mesh compression techniqueItem Metadata only Optimal sizing and location of a PV system on three-phase unbalanced radial distribution feeder avoiding reverse power flow.(IEEE, 2011) Al-Sabounchi, Ammar M. Munir; Gow, J. A.; Al-Akaidi, Marwan, 1959-; Al-Thani, H.Item Metadata only Optimal Sizing and Location of PVDG Unit on Radial Distribution Feeder allowing no Reverse Current Flow(2010) Al-Sabounchi, Ammar M. Munir; Gow, J. A.; Al-Akaidi, Marwan, 1959-; Al-Thani, H.Item Metadata only Orthogonal wavelet division multiplex: an alternative to OFDM(IEEE, 2007-01-01) Ibrahim, M. K.; Al-Akaidi, Marwan, 1959-; Linfoot, Scott L.Item Metadata only Performance evaluation of DVB-RCT return path in fading channels with added diversity(IEEE, 2007-05-01) Al-Akaidi, Marwan, 1959-; Alani, O.; Linfoot, Scott L.Item Open Access Practical channel-adaptive video streaming with fountain codes.(IEEE, 2008-10) Ahmad, Shakeel; Hamzaoui, Raouf; Al-Akaidi, Marwan, 1959-Video streaming is sensitive to packet loss, which can severely damage the quality of the received video. Video communication systems that rely on application-layer forward error correction (FEC) to combat packet loss are particularly suitable for pervasive computing because they can be used on top of any existing network architecture. However, since in heterogeneous environments network con- ditions are unpredictable, determining the right amount of redundancy introduced by the channel encoder is not obvious. This paper presents a practical implementation of a unicast video streaming system that solves this problem by using a rateless code and receiver feedback. In real simulations over the Internet our solution outperformed a standard approach based on fixed-rate forward error correction. For an Internet connection Konstanz-Beijing- Konstanz and the standard Foreman sequence compressed with the H.264 video coder, the gain in average peak signal to noise ratio exceeded 3.5 decibels at 90 kilobits per secondItem Metadata only Reducing the peak-to-average power ratio using turbo coding(IEEE, 2006-12-06) Al-Akaidi, Marwan, 1959-; Daoud, O.Item Open Access Robust live unicast video streaming with rateless codes.(IEEE, 2007-11) Ahmad, Shakeel; Hamzaoui, Raouf; Al-Akaidi, Marwan, 1959-We consider live unicast video streaming over a packet erasure channel. To protect the transmitted data, previous solutions use forward error correction (FEC), where the channel code rate is fixed in advance according to an estimation of the packet loss rate. However, these solutions are inefficient under dynamic and unpredictable channel conditions because of the mismatch between the estimated packet loss rate and the actual one.We introduce a new approach based on rateless codes and receiver feedback. For every source block, the sender keeps on transmitting the encoded symbols until it receives an acknowledgment from the receiver indicating that the block was decoded successfully. Within this framework, we provide an efficient algorithm to minimize bandwidth usage while ensuring successful decoding subject to an upper bound on the packet loss rate. Experimental results showed that compared to traditional fixed-rate FEC, our scheme provides significant bandwidth savings for the same playback quality