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This paper studies the impact of HSPA equipments and devices evolution, from 3GPP R5 to R7 ones, on the capacity of a real macro-cell network. A simulation method has been developed. It combines drive test measurements, link-level simulations, and a statistical capacity model, which provides a reliable estimate of the network radio capacity. Different receiver schemes are simulated: linear receivers...
Various standardization activities leading to 4G and beyond networks have considered the synergy of OFDMA and multihop relaying thus giving way for the fixed relay station (FRS)-based radio access network. As such, the next-generation networks will comprise a plethora of performance enhancing devices among which is the plug-and-play nomadic relay station (NRS). It is essential for such dense and inevitably...
Performance of a decode-and-forward (DF) based two-hop multiuser cooperative transmission system is usually restricted by the link quality between a base station (BS) and a relay station (RS) as the number of users grows. Thus the BS-RS link quality should be improved to enhance the performance. In this paper, we propose two-hop cooperative communication systems with multiple receive antennas at the...
This paper presents a framework based on self-organization to jointly self-optimize the spectrum assignment and the transmission power in the context of downlink OFDMA femtocell deployments. It is a distributed framework where each femtocell acts as an autonomous entity. Femtocells perform spectrum and transmission power assignment based on users' reported measurements, which are employed to sense...
Coordinated Multi-Point transmission and reception (CoMP) technique has been adopted in LTE-Advanced as one of the promising techniques because it can significantly increase the throughput of the cell edge user and the total sector throughput for both downlink and uplink transmission. Compared with conventional cellular system, CoMP can reduce inter-cell interference (ICI) significantly. On the other...
Antenna tilt is one of the most important performance tuning parameters of a cellular network, since it has a strong impact on the inter-site interference level in the system. In this paper, we present an analysis of the impact of antenna tilt on LTE coverage and capacity. Using system simulations, we study how the distribution between two types of tilt, electrical and mechanical, affects path gain...
This paper studies the different ways of extending wireless coverage for high data rates and improving the data capacity in a building. The solutions considered include deployments of single or multiple small base stations, i.e. Picocell or Femtocell, and distributed antenna system, operated on the same frequency as the macro cellular network. We look at the radio performance of each solution in a...
This paper considers the problem of subcarrier allocation in the downlink of multi-cell OFDMA networks. Firstly, a novel fractional frequency reuse architecture is proposed, where all available subcarriers are partitioned into two groups to which subcarriers are dynamically allocated. The first group is used in the center of each cell whereas the other which is partitioned into three sectors orthogonally...
In the downlink cellular network, the coordinated multi-point transmission for single-user multi-input multi-output (CoMP-SU-MIMO) is employed in Long Term Evolution Advanced (LTE-A) system, which can effectively reduce inter-cell interference for cell-edge user equipments (UEs). A novel transmission scheme with the joint proportional fairness (PF) scheduling algorithm, which does not need to allocate...
This work presents a novel approach for the avoidance of cross-tier interference in two-tier networks comprised of Orthogonal Frequency Division Multiple Access (OFDMA) macrocells and femtocells. This new technique is based on the use of Intracell HandOvers (IHOs), and it makes possible that either a macrocell or a femtocell can reassign its sub-channel or power allocation upon the detection of cross-tier...
This paper describes an implementation of a realtime multi-user multiple-input multiple-output (MU-MIMO) communication system, with cross-layer channel-aware scheduling. The system is implemented using software reconfigurable nodes that may be configured as either user terminals, or as base stations, communicating in the GSM 1800 uplink band. Three different commonly used scheduling algorithms (based...
Femtocell has been considered by the wireless industry as a promising solution not only to improve indoor coverage, but also to unload traffic from overburdened macrocell networks. In hybrid macro/femto networks, macrocells may have to share the same spectrum with femtocells, due to spectrum availability and network infrastructure considerations, in spite of potentially excessive interference caused...
Long Term Evolution represents an emerging and promising technology for providing a broadband ubiquitous Internet access. But several aspects have to be considered in order to provide an effective service to users. In particular, in this work, we consider the problem of optimizing the performance of real time downlink communications using a novel two-level scheduling algorithm. The upper level exploits...
Femtocell concept is gaining popularity as a promising way to improve resource reuse and thereby system capacity. This paper addresses a co-existence scenario where outdoor macrocell users and indoor femtocell users are located in close proximity. Impact of macro- and femtocells originated co-channel interference to the desired femto- and macrocell uplink is evaluated by means of outage probability...
This paper discusses the use of high altitude platforms, HAPs, to provide mobile communication services to on-ground customers. The paper explains the behavior of UMTS radio network in a situation, where the service is being provided by HAP and terrestrial base stations in a disaster scenario. In the disaster scenario, a set of adjacent terrestrial cellular base stations in the middle of the network...
Future cellular systems such as LTE-Advanced systems offer improved coverage, system throughput, and cell-edge throughput through the effective use of coordinated multi-point processing (CoMP). In this paper, we propose cooperative multicell automatic repeat request (ARQ), which exploits both the cooperation among base stations via backhaul links and ARQ. First, it involves minimal change in the physical-layer...
On the MU-MIMO broadcast channel, Per-User Unitary and Rate Control (PU2RC) as a practical design is proposed for emerging cellular standards in 3GPP LTE. Unfortunately, when the number of users is small, the performance of PU2RC would be degraded with the increase of codebook size. In this paper, we propose an efficient user scheduling scheme to overcome this defect in PU2RC by enlargement of user...
Incorporating relay nodes in cellular networks, e.g. UMTS/ HSPA, is beneficial for extending coverage as well as for service enhancement. In this paper we study the inter-cell interference generated by a relay-enabled cell and how this influences the performance of mobile users. The performance measures of interest are the inter-cell interference distribution, realized rates and flow throughput. Our...
Mobile terminal location is an information which is available in mobile cellular systems. Location-based inter-cell interference coordination and synchronization are studied here for the 3GPP Long Term Evolution mobile cellular system. The impact of positioning inaccuracy is also evaluated.
The LTE-Advanced (LTE-A) system is currently under development to allow for significantly higher spectral efficiency and data throughput than LTE systems. In a wireless system based on orthogonal frequency division multiplexing (OFDM) with frequency reuse factor one such as LTE, the achievable cell spectral efficiency is often limited by the inter-cell interference or coverage shortage of base stations...
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