Search

Non-orthogonal space-time block (STB) code structures used to be optimised considering a maximum-likelihood detection, but depending on the modulation order and/or the antenna number, the prohibitive complexity of such a receiver makes it infeasible in practice. Suboptimal low-complexity receiver structures like linear detectors can be applied instead, yielding degradation of performance compared with the predictions. When a forward error correction (FEC) code is used upstream of the STB code, an iterative receiver consisting of a FEC decoder and an interference canceller (IC) co-operating according to the turbo equalisation principle, can achieve near-optimal performance. This study aims to define the construction of full-rate full-diversity linear dispersion codes with reduced peak-to-average power ratio (PAPR), taking into account the serial concatenation with a FEC at the transmitter and a minimum mean square error (MMSE) turbo equaliser at the receiver. Optimisation criteria are mutual information maximisation, symbol error rate minimisation at the MMSE-IC output, full-diversity thanks to the threaded algebraic space time concept and PAPR minimisation. Explicit constructions are given and the resulting code efficiency is analysed through comparison with equivalent perfect STB codes. [ABSTRACT FROM AUTHOR]

A new space-time block code family for two transmitters, called the space-time error correcting codes (STECCs), is presented. As it is built from any linear forward error correcting code (FEC), a STECC is able to correct errors while achieving high spectral efficiencies. The key principle is the FEC linearity which is exploited to transmit linear combinations of FEC codewords to create a space-time redundancy. The proposed code exhibits interesting performance on an ISI-free block fading channel. This result is all the more true as the number of FEC codewords considered in the combination is high. [ABSTRACT FROM PUBLISHER]

In this paper, we describe an efficient approach to overcome the need for matrix inversion required in most wired applications encountered in practice. In particular, MMSE equalization based on series expansion to approximate the matrix inversion is addressed. By adjusting a scaling factor, the series expansion is directly optimized according to a fixed order with respect to a system performance criterion. In comparison with previous approaches, the resulting equalizer enables improved BER performance according to a fixed order, in addition to low complexity without the need for a complicated eigenvalue calculation procedure. [ABSTRACT FROM PUBLISHER]

Background: Gait and mobility aid assessments are important components of rehabilitation. Given the increasing use of telehealth to meet rehabilitation needs, it is important to examine the feasibility of such assessments within the constraints of telerehabilitation., Objective: The objective of this study was to examine the reliability and validity of the Tinetti Performance-Oriented Mobility Assessment gait scale (POMA-G) and cane height assessment under various video and transmission settings to demonstrate the feasibility of teleassessment., Design: This repeated-measures study compared the test performances of in-person, slow motion (SM) review, and normal-speed (NS) video ratings at various fixed frame rates (8, 15, and 30 frames per second) and bandwidth (128, 384, and 768 kB/s) configurations., Methods: Overall bias, validity, and interrater reliability were assessed for in-person, SM video, and NS video ratings, with SM video rating as the gold standard, as well as for different frame rate and bandwidth configurations within NS videos., Results: There was moderate to good interrater reliability for the POMA-G (intraclass correlation coefficient [ICC] = 0.66-0.77 across all configurations) and moderate validity for in-person (β = 0.62; 95% confidence interval [CI] = 0.37-0.87) and NS video (β = 0.74; 95% CI = 0.67-0.80) ratings compared with the SM video rating. For cane height, interrater reliability was good (ICC = 0.66-0.77), although it was significantly lower at the lowest frame rate (8 frames per second) (ICC = 0.66; 95% CI = 0.54-0.76) and bandwidth (128 kB/s) (ICC = 0.69; 95% CI = 0.57-0.78) configurations. Validity for cane height was good for both in-person (β = 0.80; 95% CI = 0.62-0.98) and NS video (β = 0.86; 95% CI = 0.81-0.90) ratings compared with SM video rating., Limitations: Some lower frame rate and bandwidth configurations may limit the reliability of remote cane height assessments., Conclusions: Teleassessment for POMA-G and cane height using typically available internet and video quality is feasible, valid, and reliable., (Published by Oxford University Press on behalf of American Physical Therapy Association 2020.)

Background There is limited research about the effects of video quality on the accuracy of assessments of physical function. Methods A repeated measures study design was used to assess reliability and validity of the finger-nose test (FNT) and the finger-tapping test (FTT) carried out with 50 veterans who had impairment in gross and/or fine motor coordination. Videos were scored by expert raters under eight differing conditions, including in-person, high definition video with slow motion review and standard speed videos with varying bit rates and frame rates. Results FTT inter-rater reliability was excellent with slow motion video (ICC 0.98-0.99) and good (ICC 0.59) under the normal speed conditions. Inter-rater reliability for FNT 'attempts' was excellent (ICC 0.97-0.99) for all viewing conditions; for FNT 'misses' it was good to excellent (ICC 0.89) with slow motion review but substantially worse (ICC 0.44) on the normal speed videos. FTT criterion validity (i.e. compared to slow motion review) was excellent (β = 0.94) for the in-person rater and good ( β = 0.77) on normal speed videos. Criterion validity for FNT 'attempts' was excellent under all conditions ( r ≥ 0.97) and for FNT 'misses' it was good to excellent under all conditions ( β = 0.61-0.81). Conclusions In general, the inter-rater reliability and validity of the FNT and FTT assessed via video technology is similar to standard clinical practices, but is enhanced with slow motion review and/or higher bit rate.

Veterans residing in underserved rural areas face many barriers to accessing high-quality rehabilitation services. This article describes the benefits and challenges of using technology for delivery of rehabilitation services to rural Veterans using TeleHOME, an innovative tele-rehabilitation program. TeleHOME enables rehabilitation providers to remotely assess the Veteran's functional abilities and needs in his or her own home where these tasks must be performed. This technology increases the ability of all team members to contribute to interdisciplinary care, but also requires greater levels of team integration. One month after the completion of the TeleHOME project, we met with clinicians to discuss their perceptions of whether and how use of the technology affected interdisciplinary care processes, and what approaches were used to meet team-based goals. TeleHOME can improve access to rehabilitation services for rural Veterans, but will also bring about novel integrative care processes that may improve the effectiveness of such services. Recommendations to overcome challenges to optimize the implementation and delivery of TeleHOME services as well as to better inform clinicians working with rural Veterans are discussed.