Avhishek Chatterjee, K. Jagannathan, Prabha Mandayam
{"title":"Qubits through Queues: The Capacity of Channels with Waiting Time Dependent Errors","authors":"Avhishek Chatterjee, K. Jagannathan, Prabha Mandayam","doi":"10.1109/NCC.2019.8732185","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732185","url":null,"abstract":"We consider a setting where qubits are processed sequentially, and derive fundamental limits on the rate at which classical information can be transmitted using quantum states that decohere in time. Specifically, we model the sequential processing of qubits using a single server queue, and derive explicit expressions for the capacity of such a ‘queue-channel.’ We also demonstrate a sweet-spot phenomenon with respect to the arrival rate to the queue, i.e., we show that there exists a value of the arrival rate of the qubits at which the rate of information transmission (in bits/sec) through the queue-channel is maximised. Next, we consider a setting where the average rate of processing qubits is fixed, and show that the capacity of the queue-channel is maximised when the processing time is deterministic. We also discuss design implications of these results on quantum information processing systems.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"39 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75007079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Detection and Estimation of Multiple DoA Targets with Single Snapshot Measurements","authors":"Rakshith Jagannath","doi":"10.1109/NCC.2019.8732225","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732225","url":null,"abstract":"In this paper, we explore the problems of detecting the number of narrow-band, far-field targets and estimating their corresponding directions of arrivals (DoAs) from single snapshot measurements. We use the principles of sparse signal recovery (SSR) for detection and estimation of multiple targets. In the SSR framework, the DoA estimation problem is grid based and can be posed as the lasso optimization problem. The corresponding DoA detection problem reduces to estimating the optimal regularization parameter $(tau)$ of the lasso problem for achieving the required probability of correct detection $(P_{c})$. We propose finite sample and asymptotic test statistics for detecting the number of sources with the required $P_{c}$ at moderate to high signal to noise ratios. Once the number of sources are detected, or equivalently the optimal $hat{tau}$ is estimated, the corresponding DoAs can be estimated by solving the lasso with regularization parameter set to $hat{tau}$.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"21 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2016-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82168443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}