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Cloud radio access network (C-RAN), regarded as a promising green network architecture, facilitates cooperative transmission among remote radio heads (RRHs) while enabling flexible computation provisioning in the virtualized baseband unit pool. By jointly optimizing cooperative transmission, i.e., transmit power allocation with zero-forcing precoding adopted, and computation provisioning, i.e., virtual...
This paper proposes an efficient method for combing multi-user MIMO (MU-MIMO) employing Tomlinson Ha-rashima precoding (THP) with semiorthogonal user selection (SUS). Although the ordering of MU-MIMO THP and SUS create space diversity benefit and multi-user diversity benefit, respectively, a significant computational effort is required, which is expected to be relaxed while retaining the system level...
This paper presents a generalized frequency division multiplexing (GFDM) communication scheme based on 4-weighted fractional Fourier transform (WFRFT) precoding. The proposed scheme as well as its low complexity version achieves flexible multi-object optimization of system performance such as bit error rate (BER) and peak to average power ratio (PAPR). Compared to traditional GFDM scheme, the improved...
Precoding is a common technique used in wireless transmissions where multiple data streams are spatially multiplexed by an access point or base station to a number of receiving stations by using multiple transmit antennas. The design of the precoder can be divided into two separate functional blocks: 1) the transmit filters, for example zero-forcing or minimum mean-square error, with unit norm columns...
In this paper, we investigate the impact of massive MIMO and distributed precoding on the performance of densified cellular networks via large system analysis. Based on the fact that the network rate performance of the cellular networks is scale invariant with reduced cell size, we want to find out if the interference of large scale dense cellular networks can be alleviated by the use of large scale...
A concept of full-dimension MIMO (FD-MIMO) adopting 2-dimensional (2D) antenna array has been proposed with intent to cope with practical challenges of massive MIMO systems. In this paper, we investigate an FD-MIMO operation that can be transparently applied with current 3GPP LTE specifications, and propose a novel method that facilitates an accurate estimation of channel quality indicator (CQI) at...
We consider downlink (DL) transmission for a Time Division Duplex (TDD) LTE base station in a target cell with centralized baseband processing for a distributed Massive MIMO antenna system. The remote antenna units of the base station, distributed geographically within the target cell, also supports baseband processing complementing the centralized baseband unit. For DL data transmission, two-stage...
For multiuser-MIMO (MU-MIMO) downlink, the authors propose a novel precoding concept of block lower multi-diagonalization. Extending the conventional block diagonalization method, the proposed precoder for the desired user is computed to incorporate a predetermined number of interfering users. Consequently, the concept enables us to ensure extra degrees of freedom at the transmit array even after...
Precoding is a common technique used in wireless transmissions where multiple data streams are spatially multiplexed by an access point or base station to a number of receiving stations by using multiple transmit antennas. The design of the precoder can be divided into two separate functional blocks: 1) the transmit filters, for example zero-forcing or minimum mean-square error, with unit norm columns...
Channel state information (CSI) is critical for the performance of multicell cooperative transmission. This paper compares two cooperative multicell precoding methods, namely, centralized precoding with global CSI and distributed precoding with local individual CSI. For both cases, the BSs have access to the data of all the users. The only difference is that in centralized precoding, the precoding...
For multiuser-MIMO (MU-MIMO) downlink, the authors propose a novel precoding concept of block lower multi-diagonalization. Extending the conventional block diagonalization method, the proposed precoder for the desired user is computed to incorporate a predetermined number of interfering users. Consequently, the concept enables us to ensure extra degrees of freedom at the transmit array even after...
Heterogeneous networks has recently evolved as one of the key enablers for future wireless technologies. The extremely growing mobile market, together with the arising demand for high data rates, force to off-load the main cellular network traffic. This can be accomplished by deploying small cells within the macro evolved-node base-station (eNodeB) coverage. Thus, more User Equipments (UEs) in the...
In the present paper we study the downlink performance of a Massive Multi-User Multiple-Input Multiple-Output narrowband system in Random Line-Of-Sight scenarios. We evaluate the ergodic sum rate for the Zero-Forcing and the Matched-Filtering precoders. We consider a single-cell system comprising a base station with 100 Huygens source antenna elements and 10 users each equipped with a single dipole...
Joint processing coordinated multipoint (JP-CoMP) is a new technology in LTE-A adopted to enhance the throughput of cell edge users as well as to mitigate interference. Relay Nodes (RNs) have also proven useful toward the realization of LTE-A, in improving the signal quality for the cell edge users. In this paper, we propose to combine JP-CoMP and relaying techniques for further improvements at the...
The major challenge in Long Term Evolution Advanced (LTE-A) based 5G network is to improve the cell capacity and cell coverage of indoor users. To fulfill these demands, low power Femto Base stations are deployed at homes and company premises. Such heterogeneous network introduces interference due to both Femtocell and microcell users, especially for cell edge users as the frequencies are reused intrusively...
Massive MIMO is used in a new generation wireless technology and a method to improve the spectral efficiency (SE) of communications systems. Nowadays, because of the users and applications that are always increasing day by day the improvement of wireless technology shall be in line according to demand. In this paper, pre-coding technique used to optimize spectral efficiency and the number of user...
Massive MIMO (multiple-input multiple-output) antenna technology can provide significant performance improvement for cellular systems in terms of both throughput and energy efficiency. It is widely recognized that inter-user interference can be eliminated with a large number of antennas because of the asymptotical orthogonality among users when linear MF (Matched Filter) downlink precoding is used...
In this paper, we show that the capacity of multi-source single-sink erasure networks can be asymptotically achieved by employing random linear network coding at the intermediate nodes over a sufficiently large number of time extensions. The main idea is to model the resulting network as a finite-field linear deterministic multiple-access channel (MAC), and show that linear precoding at the source...
In this paper, we investigate an indoor multiuser visible light communication system employing multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM). For each subcarrier in OFDM, the corresponding precoding matrix is calculated in the frequency domain to eliminate multi-user interference. The distances of the multiple transmitter-receiver links are different, which...
In multi-antenna systems, the spatial degree of freedom can be efficiently exploited to enhance the system capacity by effectively scheduling the multiple users. This article analyzes the interference based scheduling for multiuser MIMO (MU-MIMO) communication in terms of performance gains, fairness, and computational complexity. We also consider the significance of specifiec selection criteria for...
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