Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959876
Rana A. Hassan, A. Mohamed, John Tadrous, M. Nafie, T. Elbatt, F. Digham
We investigate the performance of dynamic proactive caching in relay networks where an intermediate relay station caches content for potential future use by end users. A central base station proactively controls the cache allocation such that cached content remains fresh for consumption for a limited number of time slots called proactive service window. With uncertain user demand over multiple data items and dynamically changing wireless links, we consider the optimal allocation of relay stations cache to minimize the time average expected service cost. We characterize a fundamental lower bound on the cost achieved by any proactive caching policy. Then we develop an asymptotically optimal caching policy that attains the lower bound as the proactive caching window size grows. Our analytical findings are supported with numerical simulations to demonstrate the efficiency of the proposed relay-caching.
{"title":"Dynamic proactive caching in relay networks","authors":"Rana A. Hassan, A. Mohamed, John Tadrous, M. Nafie, T. Elbatt, F. Digham","doi":"10.23919/WIOPT.2017.7959876","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959876","url":null,"abstract":"We investigate the performance of dynamic proactive caching in relay networks where an intermediate relay station caches content for potential future use by end users. A central base station proactively controls the cache allocation such that cached content remains fresh for consumption for a limited number of time slots called proactive service window. With uncertain user demand over multiple data items and dynamically changing wireless links, we consider the optimal allocation of relay stations cache to minimize the time average expected service cost. We characterize a fundamental lower bound on the cost achieved by any proactive caching policy. Then we develop an asymptotically optimal caching policy that attains the lower bound as the proactive caching window size grows. Our analytical findings are supported with numerical simulations to demonstrate the efficiency of the proposed relay-caching.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"24 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77277893","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959912
Ribal Atallah, C. Assi, Maurice J. Khabbaz
The proper design of a vehicular network is the key expeditor for establishing an efficient Intelligent Transportation System, which enables diverse applications associated with traffic safety, traffic efficiency, and the entertainment of commuting passengers. In this paper, we address both safety and Quality-of-Service (QoS) concerns in a green Vehicle-to-Infrastructure communication scenario. Using the recent advances in training deep neural networks, we present a deep reinforcement learning model, namely deep Q-network, that learns an energy-efficient scheduling policy from high-dimensional inputs corresponding to the characteristics and requirements of vehicles residing within a RoadSide Unit's (RSU) communication range. The realized policy serves to extend the lifetime of the battery-powered RSU while promoting a safe environment that meets acceptable QoS levels. Our presented deep reinforcement learning model is found to outperform both random and greedy scheduling benchmarks.
{"title":"Deep reinforcement learning-based scheduling for roadside communication networks","authors":"Ribal Atallah, C. Assi, Maurice J. Khabbaz","doi":"10.23919/WIOPT.2017.7959912","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959912","url":null,"abstract":"The proper design of a vehicular network is the key expeditor for establishing an efficient Intelligent Transportation System, which enables diverse applications associated with traffic safety, traffic efficiency, and the entertainment of commuting passengers. In this paper, we address both safety and Quality-of-Service (QoS) concerns in a green Vehicle-to-Infrastructure communication scenario. Using the recent advances in training deep neural networks, we present a deep reinforcement learning model, namely deep Q-network, that learns an energy-efficient scheduling policy from high-dimensional inputs corresponding to the characteristics and requirements of vehicles residing within a RoadSide Unit's (RSU) communication range. The realized policy serves to extend the lifetime of the battery-powered RSU while promoting a safe environment that meets acceptable QoS levels. Our presented deep reinforcement learning model is found to outperform both random and greedy scheduling benchmarks.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"5 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86284517","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959884
Jae-Ho Jeong, Jeongho Kwak, S. Chong
In this paper, we study a joint beam and user scheduling problem in a cooperative cellular network utilizing orthogonal random beamforming technique. This paper aims to minimize total base stations' average energy expenditure while ensuring finite service time for all traffic arrivals in a given set. We leverage Lyapunov optimization technique to transform original long-term problem into short-term modified max-weight problem without knowledge of future network states such as traffic arrivals. We introduce a parameter which manipulates energy-delay tradeoff in our system as well. Since provided short-term problem is combinatorial and nonlinear optimization problem, we are inspired by a greedy algorithm to design near-optimal joint beam and user scheduling policy, namely BEANS. We prove that proposed BEANS (i) ensures finite service time for all traffic arrival rates within close to 1/2 capacity region and all (energy-delay) tradeoff parameters thanks to submodular characteristics of the objective function, and (ii) attains finite upper bounds of average energy consumption and average queue backlog for all traffic arrival rates within close to 1/4 capacity region and all tradeoff parameters. Finally, via extensive simulations, we compare the capacity region and energy-queue backlog tradeoff of BEANS with optimal and existing algorithms, and show that BEANS attains 43% of energy saving for the same average queue backlog compared to the algorithms which do not take traffic dynamics and energy consumption into considerations.
{"title":"Energy-efficient beam scheduling for orthogonal random beamforming in cooperative networks","authors":"Jae-Ho Jeong, Jeongho Kwak, S. Chong","doi":"10.23919/WIOPT.2017.7959884","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959884","url":null,"abstract":"In this paper, we study a joint beam and user scheduling problem in a cooperative cellular network utilizing orthogonal random beamforming technique. This paper aims to minimize total base stations' average energy expenditure while ensuring finite service time for all traffic arrivals in a given set. We leverage Lyapunov optimization technique to transform original long-term problem into short-term modified max-weight problem without knowledge of future network states such as traffic arrivals. We introduce a parameter which manipulates energy-delay tradeoff in our system as well. Since provided short-term problem is combinatorial and nonlinear optimization problem, we are inspired by a greedy algorithm to design near-optimal joint beam and user scheduling policy, namely BEANS. We prove that proposed BEANS (i) ensures finite service time for all traffic arrival rates within close to 1/2 capacity region and all (energy-delay) tradeoff parameters thanks to submodular characteristics of the objective function, and (ii) attains finite upper bounds of average energy consumption and average queue backlog for all traffic arrival rates within close to 1/4 capacity region and all tradeoff parameters. Finally, via extensive simulations, we compare the capacity region and energy-queue backlog tradeoff of BEANS with optimal and existing algorithms, and show that BEANS attains 43% of energy saving for the same average queue backlog compared to the algorithms which do not take traffic dynamics and energy consumption into considerations.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"8 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87255834","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959929
A. Afzal, Afef Feki, M. Debbah, Syed Ali Raza Zaidi, M. Ghogho, D. McLernon
In this article, we investigate how the performance of Massive MIMO cellular systems can be enhanced by introducing D2D communication. We consider a scenario where the base station (BS) is equipped with large, but finite number of antennas and the total number of UEs is kept fixed. The key design question is that what fraction of users should be offloaded to D2D mode in order to maximize the aggregate cell level throughput. We demonstrate that there exists an optimal user offload fraction, which maximizes the overall capacity. This fraction is strongly coupled with the network parameters such as the number of antennas at the BS, D2D link distance and the transmit SNR at both the UE and the BS and careful tuning of the offload fraction can provide up to 5× capacity gains.1
{"title":"Leveraging D2D communication to maximize the spectral efficiency of Massive MIMO systems","authors":"A. Afzal, Afef Feki, M. Debbah, Syed Ali Raza Zaidi, M. Ghogho, D. McLernon","doi":"10.23919/WIOPT.2017.7959929","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959929","url":null,"abstract":"In this article, we investigate how the performance of Massive MIMO cellular systems can be enhanced by introducing D2D communication. We consider a scenario where the base station (BS) is equipped with large, but finite number of antennas and the total number of UEs is kept fixed. The key design question is that what fraction of users should be offloaded to D2D mode in order to maximize the aggregate cell level throughput. We demonstrate that there exists an optimal user offload fraction, which maximizes the overall capacity. This fraction is strongly coupled with the network parameters such as the number of antennas at the BS, D2D link distance and the transmit SNR at both the UE and the BS and careful tuning of the offload fraction can provide up to 5× capacity gains.1","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"4 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86236884","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959947
Chao Fang, Behrooz Makki, T. Svensson
Cellular networks operating at millimeter wave (mmWave) frequencies are able to achieve multi-gigabit-per-second data rates due to the large bandwidth available. However, the data transmission range will be shorter and significant signal power difference will be observed between line-of-sight (LOS) and non-line-of-sight (NLOS) links. This paper considers interference management and useful signal enhancement in the uplink transmission of small-cell mmWave networks. Taking blockages into account, we analyze the coverage performance of the partial-zero-forcing (PZF) receiver which utilizes a number of antennas to cancel out the strongest uplink interferers and uses the rest of the antennas for boosting the useful signal. Using stochastic geometry, we derive analytical expressions for the coverage probability of the PZF receiver under a LOS probability function based path loss model. For a broad range of parameter settings, the maximum coverage probability is achieved by using most antennas for array gain and only canceling a few strongest interferers. Particularly, compared to zero-forcing, the PZF scheme can improve the coverage probability significantly.
{"title":"Coverage analysis for millimeter wave uplink cellular networks with partial zero-forcing receivers","authors":"Chao Fang, Behrooz Makki, T. Svensson","doi":"10.23919/WIOPT.2017.7959947","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959947","url":null,"abstract":"Cellular networks operating at millimeter wave (mmWave) frequencies are able to achieve multi-gigabit-per-second data rates due to the large bandwidth available. However, the data transmission range will be shorter and significant signal power difference will be observed between line-of-sight (LOS) and non-line-of-sight (NLOS) links. This paper considers interference management and useful signal enhancement in the uplink transmission of small-cell mmWave networks. Taking blockages into account, we analyze the coverage performance of the partial-zero-forcing (PZF) receiver which utilizes a number of antennas to cancel out the strongest uplink interferers and uses the rest of the antennas for boosting the useful signal. Using stochastic geometry, we derive analytical expressions for the coverage probability of the PZF receiver under a LOS probability function based path loss model. For a broad range of parameter settings, the maximum coverage probability is achieved by using most antennas for array gain and only canceling a few strongest interferers. Particularly, compared to zero-forcing, the PZF scheme can improve the coverage probability significantly.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"8 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72593143","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959868
S. Pattathil, J. Nair
We consider the problem of optimal distributed scheduling for delay minimization in single-hop wireless networks. We focus on static scheduling policies, where the CSMA channel access rates are determined by the long-run traffic statistics, but not the instantaneous queue states. Such static scheduling is preferable over dynamic scheduling policies like max-weight when the traffic flows are heterogeneous. In this paper, we formulate the problem of optimizing the channel access rates of different links subject to an upper bound on the access rate of each link. This is a hard non-convex optimization. We propose an approximate solution that is asymptotically optimal in the limit as the maximum permissible channel access rate grows to infinity. We also study the role of the intra-queue scheduling policy. Specifically, we consider two policies: first come first served (FCFS) and pre-emptive last come first served (PLCFS). Analogous to the case of an M/G/1 queue, we show that PLCFS is preferable to FCFS for highly variable flows.
{"title":"Optimal distributed scheduling for single-hop wireless networks","authors":"S. Pattathil, J. Nair","doi":"10.23919/WIOPT.2017.7959868","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959868","url":null,"abstract":"We consider the problem of optimal distributed scheduling for delay minimization in single-hop wireless networks. We focus on static scheduling policies, where the CSMA channel access rates are determined by the long-run traffic statistics, but not the instantaneous queue states. Such static scheduling is preferable over dynamic scheduling policies like max-weight when the traffic flows are heterogeneous. In this paper, we formulate the problem of optimizing the channel access rates of different links subject to an upper bound on the access rate of each link. This is a hard non-convex optimization. We propose an approximate solution that is asymptotically optimal in the limit as the maximum permissible channel access rate grows to infinity. We also study the role of the intra-queue scheduling policy. Specifically, we consider two policies: first come first served (FCFS) and pre-emptive last come first served (PLCFS). Analogous to the case of an M/G/1 queue, we show that PLCFS is preferable to FCFS for highly variable flows.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"76 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79515968","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959935
Helena Rocha, Gwenaelle Delsart, Alexandro Andersson, Ayoub Bousselmi, A. Conte, A. Gati, A. Masucci, Christophe Grangeat, C. Cavdar, D. Marquet, E. Alexandri, Gregory Akpoli-Johnson, H. Scheck, Juan Gascon, L. Nuaymi, L. Salahaldin, Mamdouh El Tabach, M. M. A. Hossain, S. Elayoubi, Sofiane Imadali, T. Chahed, Vilho Jonsson, Wilfried Yoro, Xavier Campderros
Today, mobile networks are witnessing an exponential growth of traffic volumes, linked to new services, especially for smart cities and smart-grid. The European Celtic-Plus SooGREEN project, started mid 2015, is targeting to reduce the energy consumption of the services in different mobile architectures in interaction with smart-grid. So GREEN is focused on the services energy consumption modelling and measurement, the dynamic optimization of the mobile access network and of the content delivery, the design of an Energy Efficient Virtualized and Centralized Radio Access Network (RAN), and the bi-directional interaction of the mobile network with the smart-grid. This paper presents insight into the project after its first year, and discusses research trends in green communication networks for the future.
{"title":"SooGREEN: Service-oriented optimization of green mobile networks","authors":"Helena Rocha, Gwenaelle Delsart, Alexandro Andersson, Ayoub Bousselmi, A. Conte, A. Gati, A. Masucci, Christophe Grangeat, C. Cavdar, D. Marquet, E. Alexandri, Gregory Akpoli-Johnson, H. Scheck, Juan Gascon, L. Nuaymi, L. Salahaldin, Mamdouh El Tabach, M. M. A. Hossain, S. Elayoubi, Sofiane Imadali, T. Chahed, Vilho Jonsson, Wilfried Yoro, Xavier Campderros","doi":"10.23919/WIOPT.2017.7959935","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959935","url":null,"abstract":"Today, mobile networks are witnessing an exponential growth of traffic volumes, linked to new services, especially for smart cities and smart-grid. The European Celtic-Plus SooGREEN project, started mid 2015, is targeting to reduce the energy consumption of the services in different mobile architectures in interaction with smart-grid. So GREEN is focused on the services energy consumption modelling and measurement, the dynamic optimization of the mobile access network and of the content delivery, the design of an Energy Efficient Virtualized and Centralized Radio Access Network (RAN), and the bi-directional interaction of the mobile network with the smart-grid. This paper presents insight into the project after its first year, and discusses research trends in green communication networks for the future.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"21 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77722227","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959866
S. Chatterjee, Mohammad J. Abdel-Rahman, A. B. Mackenzie
Since LTE in unlicensed spectrum (LTE-U) was proposed by Qualcomm, it has drawn considerable interest because of its potential to increase the capacity of existing LTE networks by utilizing existing infrastructure in the unlicensed band. But, Wi-Fi technology, already operating in the unlicensed 5 GHz band, creates several potential challenges for managing the activities of these two different technologies in the same band. In this context, we propose an adaptive coexistence scheme between LTE and WiFi by utilizing almost blank subframes (ABS). An ABS is an LTE subframe of duration 1 ms (containing two time slots of 0.5 ms duration) with reduced downlink activity. LTE allocates ABSs over 20 MHz channels in 5 GHz band to allow WiFi to access the spectrum. In the proposed coexistence scheme, each LTE cell optimally distributes ABSs over the frame to provide certain quality of service (QoS) guarantees for WiFi traffic while ensuring the performance of its own users.
{"title":"Optimal distributed allocation of almost blank subframes for LTE/WiFi coexistence","authors":"S. Chatterjee, Mohammad J. Abdel-Rahman, A. B. Mackenzie","doi":"10.23919/WIOPT.2017.7959866","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959866","url":null,"abstract":"Since LTE in unlicensed spectrum (LTE-U) was proposed by Qualcomm, it has drawn considerable interest because of its potential to increase the capacity of existing LTE networks by utilizing existing infrastructure in the unlicensed band. But, Wi-Fi technology, already operating in the unlicensed 5 GHz band, creates several potential challenges for managing the activities of these two different technologies in the same band. In this context, we propose an adaptive coexistence scheme between LTE and WiFi by utilizing almost blank subframes (ABS). An ABS is an LTE subframe of duration 1 ms (containing two time slots of 0.5 ms duration) with reduced downlink activity. LTE allocates ABSs over 20 MHz channels in 5 GHz band to allow WiFi to access the spectrum. In the proposed coexistence scheme, each LTE cell optimally distributes ABSs over the frame to provide certain quality of service (QoS) guarantees for WiFi traffic while ensuring the performance of its own users.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"29 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84290188","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959904
Panos N. Alevizos, Xiao Fu, N. Sidiropoulos, Ye Yang, A. Bletsas
This work proposes a new limited feedback channel estimation framework. The proposed approach exploits a sparse representation of the double directional wireless channel model involving an over complete dictionary that accounts for the antenna directivity patterns at both base station (BS) and user equipment (UE). Under this sparse representation, a computationally efficient limited feedback algorithm that is based on single-bit compressive sensing is proposed to effectively estimate the downlink channel. The algorithm is lightweight in terms of computation, and suitable for real-time implementation in practical systems. More importantly, under our design, using a small number of feedback bits, very satisfactory channel estimation accuracy is achieved even when the number of BS antennas is very large, which makes the proposed scheme ideal for massive MIMO 5G cellular networks. Judiciously designed simulations reveal that the proposed algorithm outperforms a number of popular feedback schemes in terms of beam forming gain for subsequent downlink transmission, and reduces feedback overhead substantially when the BS has a large number of antennas.
{"title":"Non-uniform directional dictionary-based limited feedback for massive MIMO systems","authors":"Panos N. Alevizos, Xiao Fu, N. Sidiropoulos, Ye Yang, A. Bletsas","doi":"10.23919/WIOPT.2017.7959904","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959904","url":null,"abstract":"This work proposes a new limited feedback channel estimation framework. The proposed approach exploits a sparse representation of the double directional wireless channel model involving an over complete dictionary that accounts for the antenna directivity patterns at both base station (BS) and user equipment (UE). Under this sparse representation, a computationally efficient limited feedback algorithm that is based on single-bit compressive sensing is proposed to effectively estimate the downlink channel. The algorithm is lightweight in terms of computation, and suitable for real-time implementation in practical systems. More importantly, under our design, using a small number of feedback bits, very satisfactory channel estimation accuracy is achieved even when the number of BS antennas is very large, which makes the proposed scheme ideal for massive MIMO 5G cellular networks. Judiciously designed simulations reveal that the proposed algorithm outperforms a number of popular feedback schemes in terms of beam forming gain for subsequent downlink transmission, and reduces feedback overhead substantially when the BS has a large number of antennas.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"48 4","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91501916","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}
Pub Date : 2017-05-15DOI: 10.23919/WIOPT.2017.7959863
Felix Engelmann, P. Elia
Coded caching is a communications technique that has elevated the preemptive use of memory (caching) into a powerful ingredient in general communications networks, promising to change the way networking and PHY-based communications are conducted. At the same time though — because this approach is heavily dependent on cooperation between the content provider (CP), and a centralized powerful transmitter of information (ISP), and because it is heavily dependent on users caching a variety of content that is not their own — raises privacy concerns which have the potential to compromise the applicability of coded caching. What we are showing in this early work here, is that in fact coded caching carries a distinct set of salient features that in fact boost privacy. We present a step-by-step privacy-aware content-delivery protocol that utilizes caching and which — at a small cost in performance — can safeguard against unauthorized matching of users to their requests, as well as against unauthorized knowledge of the popularity statistics of files; both crucial privacy issues in different scenarios such as video on demand. These properties include multicasting-only transmissions for continuous obfuscation of the true destination of content, an almost seamless addition of phantom users that can skew the true popularity distribution, popularity-agnostic caches, cache-agnostic ISP, and an overall minimization of data traffic between CP and ISP, and between ISP and users.
{"title":"A content-delivery protocol, exploiting the privacy benefits of coded caching","authors":"Felix Engelmann, P. Elia","doi":"10.23919/WIOPT.2017.7959863","DOIUrl":"https://doi.org/10.23919/WIOPT.2017.7959863","url":null,"abstract":"Coded caching is a communications technique that has elevated the preemptive use of memory (caching) into a powerful ingredient in general communications networks, promising to change the way networking and PHY-based communications are conducted. At the same time though — because this approach is heavily dependent on cooperation between the content provider (CP), and a centralized powerful transmitter of information (ISP), and because it is heavily dependent on users caching a variety of content that is not their own — raises privacy concerns which have the potential to compromise the applicability of coded caching. What we are showing in this early work here, is that in fact coded caching carries a distinct set of salient features that in fact boost privacy. We present a step-by-step privacy-aware content-delivery protocol that utilizes caching and which — at a small cost in performance — can safeguard against unauthorized matching of users to their requests, as well as against unauthorized knowledge of the popularity statistics of files; both crucial privacy issues in different scenarios such as video on demand. These properties include multicasting-only transmissions for continuous obfuscation of the true destination of content, an almost seamless addition of phantom users that can skew the true popularity distribution, popularity-agnostic caches, cache-agnostic ISP, and an overall minimization of data traffic between CP and ISP, and between ISP and users.","PeriodicalId":6630,"journal":{"name":"2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)","volume":"31 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84762124","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}
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