Distributed Quasi-Orthogonal Space-Time coding in wireless cooperative relay networks

Cooperative diversity provides a new paradigm in robust wireless re- lay networks that leverages Space-Time (ST) processing techniques to combat the effects of fading. Distributing the encoding over multiple relays that potentially observe uncorrelated channels to a destination terminal has demonstrated promising results in extending range, data- rates and transmit power utilization. Specifically, Space Time Block Codes (STBCs) based on orthogonal designs have proven extremely popular at exploiting spatial diversity through simple distributed pro- cessing without channel knowledge at the relaying terminals. This thesis aims at extending further the extensive design and analysis in relay networks based on orthogonal designs in the context of Quasi- Orthogonal Space Time Block Codes (QOSTBCs). The characterization of Quasi-Orthogonal MIMO channels for cooper- ative networks is performed under Ergodic and Non-Ergodic channel conditions. Specific to cooperative diversity, the sub-channels are as- sumed to observe different shadowing conditions as opposed to the traditional co-located communication system. Under Ergodic chan- nel assumptions novel closed-form solutions for cooperative channel capacity under the constraint of distributed-QOSTBC processing are presented. This analysis is extended to yield closed-form approx- imate expressions and their utility is verified through simulations. The effective use of partial feedback to orthogonalize the QOSTBC is examined and significant gains under specific channel conditions are demonstrated. Distributed systems cooperating over the network introduce chal- lenges in synchronization. Without extensive network management it is difficult to synchronize all the nodes participating in the relaying between source and destination terminals. Based on QOSTBC tech- niques simple encoding strategies are introduced that provide compa- rable throughput to schemes under synchronous conditions with neg- ligible overhead in processing throughout the protocol. Both mutli- carrier and single-carrier schemes are developed to enable the flexi- bility to limit Peak-to-Average-Power-Ratio (PAPR) and reduce the Radio Frequency (RF) requirements of the relaying terminals. The insights gained in asynchronous design in flat-fading cooperative channels are then extended to broadband networks over frequency- selective channels where the novel application of QOSTBCs are used in distributed-Space-Time-Frequency (STF) coding. Specifically, cod- ing schemes are presented that extract both spatial and mutli-path diversity offered by the cooperative Multiple-Input Multiple-Output (MIMO) channel. To provide maximum flexibility the proposed schemes are adapted to facilitate both Decode-and-Forward (DF) and Amplify- and-Forward (AF) relaying. In-depth Pairwise-Error-Probability (PEP) analysis provides distinct design specifications which tailor the distributed- STF code to maximize the diversity and coding gain offered under the DF and AF protocols. Numerical simulation are used extensively to confirm the validity of the proposed cooperative schemes. The analytical and numerical re- sults demonstrate the effective use of QOSTBC over orthogonal tech- niques in a wide range of channel conditions

Exploitation of quasi-orthogonal space time block codes in virtual antenna arrays: part I - theoretical capacity and throughput gains

A full-rate and full-diversity closed-loop quasi-orthogonal space time block coding scheme pioneered by Toker, Lambotharan and Chambers is proposed for application in virtual antenna arrays. The theoretical capacity and throughput gains are evaluated as a function of signal-to-noise ratio. It is shown that the scheme has particular benefits in both ergodic and non-ergodic channel environments, and outperforms virtual antenna arrays based solely upon conventional orthogonal space time block codes

Exploitation of quasi-orthogonal space time block codes in virtual antenna arrays: part II Monte Carlo-based throughput evaluation

A full rate and full diversity closed-loop quasi-orthogonal space time block coding scheme due to Toker, Lambotharan and Chambers is proposed for application in virtual antenna arrays. The performance gain is achieved through closed-loop operation involving feedback of phase rotation angle(s) calculated from channel state information (CSI) to the transmitter array. Throughput performance of the proposed scheme, with and without power optimisation, is investigated through Monte Carlo simulation with QPSK constellation signals. The results confirm the improvement in throughput performance over orthogonal space time block codes

A multi-channel opto-electronic sensor to accurately monitor heart rate against motion artefact during exercise

This study presents the use of a multi-channel opto-electronic sensor (OEPS) to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR) efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA), and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05); a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001); the bias of BAA 0.85 bpm, the standard deviation (SD) 9.20 bpm, and the limits of agreement (LOA) from −17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001); the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from −15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate

Comparison of deletion results from three different approaches.

<p>The three constructed sets of reliable events are: R_I) intersection of events from the 1KG project and events predicted by any method; R_II) events predicted by at least two methods; R_III) events from Kidd et al. The three approaches are SVMiner (SVM), BreakDancerMax (BDM) and VariationHunterWeighted (VHW).</p

Structural variants and the read pairs that support them.

<p>Pairs from a donor genome “D” have distinct characteristics when mapped to a reference genome “R” for different types of structure variants.</p

Predicted deletion events and their uncertainty scores.

<p>(a) The clustering results of the candidate deletions of dataset I (NA18507). (b) Plot of uncertainty for predicted results from the same dataset. Uncertainty is defined as 1−<i>z</i>, where <i>z</i> is the greatest of the class membership probabilities after clustering. The larger, darker circles indicate lower membership probabilities for the given data point. The highest degrees of uncertainties are around cluster boundaries and around the origin where the data features are not prominent enough to allow for a more confident prediction. Data points with prominent features (i.e. high concordant pair depth and/or high number of discordant pairs) are generally classified with high confidence. (c) The clustering results of the candidate deletions of dataset III (chromosome X of NA07340).</p

Inversion results.

<p>The result of the predicted inversions for the NA18507 specimen. The blue points are predicted inversions and the red points are classified as no events.</p

The overlaps among predicted inversion events.

<p>The overlaps among predicted inversion events by SVMiner, three versions of VariationHunter, and the events detected using a different technology (Kidd et al). The total number of events by each approach is provided in the parentheses.</p

Overlaps between SVMiner and MoDIL, and between SVMiner and BreakDancerMax on sample NA18507.

<p>Top: summary of overlaps between SVMiner and MoDIL for homozygous deletions (a) and heterozygous deletions (b). Bottom: overlaps between shorter read data and longer read data for SVMiner (c) and BreakDancerMax (d).</p