Results 11  20
of
52
Secrecy rates in the broadcast channel with confidential messages and external eavesdroppers,” submitted to
 IEEE Trans. Wireless Commun
"... ar ..."
(Show Context)
Interference management in 5G reverse TDD HetNets: A large system analysis
 IEEE J. SEL. AREAS COMMUN
, 2014
"... ..."
(Show Context)
Large System Analysis of Linear Precoding in MISO Broadcast Channels with Confidential Messages
"... In this paper, we study the performance of regularized channel inversion (RCI) precoding in large MISO broadcast channels with confidential messages (BCC). We obtain a deterministic approximation for the achievable secrecy sumrate which is almost surely exact as the number of transmit antennas M a ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
(Show Context)
In this paper, we study the performance of regularized channel inversion (RCI) precoding in large MISO broadcast channels with confidential messages (BCC). We obtain a deterministic approximation for the achievable secrecy sumrate which is almost surely exact as the number of transmit antennas M and the number of users K grow to infinity in a fixed ratio β = K/M. We derive the optimal regularization parameter ξ and the optimal network load β that maximize the perantenna secrecy sumrate. We then propose a linear precoder based on RCI and power reduction (RCIPR) that significantly increases the highSNR secrecy sumrate for 1 < β < 2. Our proposed precoder achieves a peruser secrecy rate which has the same highSNR scaling factor as both the following upper bounds: (i) the rate of the optimum RCI precoder without secrecy requirements, and (ii) the secrecy capacity of a singleuser system without interference. Furthermore, we obtain a deterministic approximation for the secrecy sumrate achievable by RCI precoding in the presence of channel state information (CSI) error. We also analyze the performance of our proposed RCIPR precoder with CSI error, and we determine how the error must scale with the SNR in order to maintain a given rate gap to the case with perfect CSI. Index Terms Physical layer security, broadcast channel, random matrix theory, linear precoding, multiuser systems. ar X iv
Asymptotic analysis of downlink MISO systems over Rician fading channels,” in
 Proc. IEEE ICASSP,
, 2016
"... ABSTRACT In this work, we focus on the ergodic sum rate in the downlink of a singlecell largescale multiuser MIMO system in which the base station employs N antennas to communicate with K singleantenna user equipments. A regularized zeroforcing (RZF) scheme is used for precoding under the assu ..."
Abstract

Cited by 2 (1 self)
 Add to MetaCart
(Show Context)
ABSTRACT In this work, we focus on the ergodic sum rate in the downlink of a singlecell largescale multiuser MIMO system in which the base station employs N antennas to communicate with K singleantenna user equipments. A regularized zeroforcing (RZF) scheme is used for precoding under the assumption that each link forms a spatially correlated MIMO Rician fading channel. The analysis is conducted assuming N and K grow large with a non trivial ratio and perfect channel state information is available at the base station. Recent results from random matrix theory and large system analysis are used to compute an asymptotic expression of the signaltointerferenceplusnoise ratio as a function of the system parameters, the spatial correlation matrix and the Rician factor. Numerical results are used to evaluate the performance gap in the finite system regime under different operating conditions.
Physical layer security in downlink multiantenna cellular networks,” submitted to
 IEEE Trans. Commun
"... All intext references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. ..."
Abstract

Cited by 2 (2 self)
 Add to MetaCart
(Show Context)
All intext references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
1Spatial Blanking and InterTier Coordination in MassiveMIMO Heterogeneous Cellular Networks
"... Abstract—This paper studies intertier interference coordination in a heterogeneous cellular network (HetNet) consisting of “massiveMIMO ” macrocells and multiantenna small cells. We assume that the users are concentrated at certain areas of the cell forming hotspots. Assuming the hotspot size to ..."
Abstract

Cited by 2 (2 self)
 Add to MetaCart
(Show Context)
Abstract—This paper studies intertier interference coordination in a heterogeneous cellular network (HetNet) consisting of “massiveMIMO ” macrocells and multiantenna small cells. We assume that the users are concentrated at certain areas of the cell forming hotspots. Assuming the hotspot size to be much smaller than the macrocell size, the users of a given hotspot are seen under a relatively narrow angular spread from the macrocell, thus appearing almost colocated to the macrocell. This gives rise to directional channel vectors, which can be exploited to simplify precoder design and obtain spatial blanking, a means of concentrating energy in the direction of scheduled hotspots, while mitigating interference caused to the active small cells located in the other directions. We further show that significant throughput gains can be achieved by complementing spatial blanking with active interference coordination strategies, such as turning OFF a small cell when it suffers from or causes excessive interference, or offloading macrocell hotspots to small cells. Index Terms—MassiveMIMO, heterogeneous cellular networks, hotspots, interference coordination, spatial blanking. I.
On the Achievable Rates of FDD Massive MIMO Systems with Spatial Channel Correlation
"... Abstract—In this paper, we study the optimization of the achievable rates of frequencydivisionduplex (FDD) massive multipleinputmultipleoutput (MIMO) systems with spatially correlated channels, by designing the downlink channel training sequences and the uplink channel feedback codebooks. In pa ..."
Abstract

Cited by 2 (2 self)
 Add to MetaCart
(Show Context)
Abstract—In this paper, we study the optimization of the achievable rates of frequencydivisionduplex (FDD) massive multipleinputmultipleoutput (MIMO) systems with spatially correlated channels, by designing the downlink channel training sequences and the uplink channel feedback codebooks. In particular, the optimal channel training sequences and a KarhunenLoeve transform followed by entropy coded scalar quantization codebook are proposed to optimize the achievable rates. We compare our achievable rates with timedivisionduplex (TDD) massive MIMO systems, i.i.d. FDD systems, and the joint spatial division and multiplexing (JSDM) scheme. It is shown that, the rategap between FDD systems and TDD systems is significantly narrowed. Compared to the JSDM scheme, our proposal achieves dimensionalityreduction channel estimation without channel preprojection, and higher throughput in general, though at higher computational complexity. I.
Optimal power allocation and user loading for multiuser MISO channels with regularized channel inversion
 IEEE Trans. Commun
, 2013
"... Abstract—We consider a multiuser system where a single transmitter equipped with multiple antennas (the base station) communicates with multiple users each with a single antenna. Regularized channel inversion is employed as the precoding strategy at the base station. Within this scenario we are inte ..."
Abstract

Cited by 2 (0 self)
 Add to MetaCart
(Show Context)
Abstract—We consider a multiuser system where a single transmitter equipped with multiple antennas (the base station) communicates with multiple users each with a single antenna. Regularized channel inversion is employed as the precoding strategy at the base station. Within this scenario we are interested in the problems of power allocation and user admission control so as to maximize the system throughput, i.e., which users should we communicate with and what power should we use for each of the admitted users so as to get the highest sum rate. This is in general a very difficult problem but we do two things to allow some progress to be made. Firstly we consider the large system regime where the number of antennas at the base station is large along with the number of users. Secondly we cluster the downlink path gains of users into a finite number of groups. By doing this we are able to show that the optimal power allocation under an average transmit power constraint follows the wellknown water filling scheme. We also investigate the user admission problem which reduces in the large system regime to optimization of the user loading in the system. Index Terms—Multiuser precoding, regularized channel inversion, power allocation, large system analysis. I.
Secrecy sumrates with regularized channel inversion precoding under imperfect CSI at the transmitter
 in Proc. Internat. Conf. Acoust. Speech Signal Process. (ICASSP
, 2013
"... ar ..."
(Show Context)
Optimal Number of Base Station Antennas and Users in MF Based Multiuser Massive MIMO Systems
"... 본 논문 은 다 중 사용 자 (multiuser) 다 중 안테 나 (MIMO, multipleinput and multipleoutput) 시스템 을 기반으로 ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
본 논문 은 다 중 사용 자 (multiuser) 다 중 안테 나 (MIMO, multipleinput and multipleoutput) 시스템 을 기반으로