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Capacity and Coverage are the two major concerns for the wireless operators to deploy cellular networks. This paper investigates the uplink capacity and coverage of relay-assisted UMTS network when multiuser detection techniques are employed at both macrocell base station (BS) and relay station (RS). A hierarchical geometric system model is used where the fixed relay stations are deployed within the...
The deployment of new networks based on 3G and beyond as well as Long Term Evolution (LTE) technologies is accelerating worldwide to satisfy the ever-increasing user appetite for higher data rates. The new deployed base stations and power amplifier requirements are exerting pressure on the relative electrical grids as well as increasing the CO2 emissions substantially. It has been reported that more...
This paper considers the problem of dynamic spectrum allocation (DSA) in the adjacent regions controlled by each spectrum broker (SB). In this scenario, the SB has a responsibility to allocate the spectrum to network service providers (NSPs) in region that SB controls. However, the SB cannot manage the interference arising between regions, and, therefore, the quality of allocated spectrum cannot be...
One of the outcomes in the last world radio communication conference 2007 (WRC-07) is assigning the 790-862 MHz band to the digital broadcasting (DB), and the new mobile system called International Mobile Telecommunication - Advanced (IMT-A) in co-primary basis in 2015. Until that year, the primary service (i.e., DB) should be protected from the new system (i.e., IMT-A). This paper investigates the...
Communication devices market becomes more oriented to multi-purpose devices supporting multi-standards simultaneously. This market trend creates a demand for receivers with ability to receive multi-frequency signals. Besides, we need to save chip cost, area, and power consumption. Direct conversion sub-sampling receiver architecture is one of the most suitable candidates for multi-standard reception...
This paper discusses the problems and constraints associated with operating femtocells on the same frequency as the macro system. It addresses questions relating to managing femtocell transmitter power to provide coverage without interfering with the macro system, and to do so especially when the femtocell is located close to a neighboring macrocell. It discusses techniques that can be used to better...
In the future, the technology of femtocell application („home base stations“) will most likely enable reduction of costs for telecommunications provider. This paper presents the installation and use of femtocells, as well as the problems one may encounter during this process. The possibilities of implementation of new equipment to existing mobile networks are also discussed.
B3G or 4G systems present different Radio Access Technologies (RAT). These networks are interconnected to improve spectral efficiency, extend service ranges and provide seamless mobility for multi-RAT mobile users. The seamless mobility refers to the network capability of providing continuous services when a mobile user is crossing different RATs. Heterogeneous networks will be seamlessly integrated...
In this paper we investigate limitations facing high rate transmission in the downlink of UMTS systems. A solution is proposed based on space-time filtering to allow parallel channel transmission and spreading code reuse. The optimum receiver is derived taking into consideration non-ideality in space-time filtering caused by channel estimation errors. Comparisons with ordinary CDMA receivers, based...
A possible mobile spectrum allocation for mobile operators that offer 2G/3G services is WCDMA 2100MHz system co-existing with a GSM 1900MHz system in the same coverage area. In this scenario inter-band interference exists at mobile subscriber (MS)/user equipment (UE) level and network/base transceiver station (BTS/Node B) level, and the objective of this paper is to observe this behavior. For that...
Spurred by the increasing demand for mobile broadband services and the growing number of devices supporting multiple radio access technologies (e.g., cellular, WiMAX, Wi-Fi, Bluetooth), much research is being done to improve the user experience while addressing issues related to network efficiency, congestion, interference, and cost to operators, service providers, manufacturers, and consumers alike...
Power efficiency is an important issue in mobile communication systems. Especially for mobile user equipments (UE), the energy budget, limited by a battery, has to be treated carefully. In fact, though, quite an amount of energy is wasted in todays UEs, as analog and digital frontend (AFE/DFE) in communication systems are designed for worst case scenarios. Therefore, for most real transmission processes...
Hutchison 3G is the first operator to launch a nationwide 3G UMTS network in the UK in 2003 to offer voice, video and data services to its customers. Hutchison 3G under the brand name of '3' launched 3GPP Rel 5 HSDPA networks worldwide. The network is capable of delivering data rates upto 14 Mbps nowadays. In Rel 7, 3GPP standardised HSPA Evolution (HSPA+) which was specified to deliver maximum user...
In today's cellular networks, it becomes harder to provide the resources for the increasing and fluctuating traffic demand exactly in the place and at the time where and when they are needed. Moreover, a cellular network which can cover indoor areas and hot-spots is a complicated and expensive task. Therefore, a new hierarchical topology is put forward to solve the problem, and the topology have application...
Femto-cells promise substantial gains in system spectral efficiency due to an enhanced reuse of radio resources. Femto-cells may be employed in a co-channel fashion such that the bandwidth used by the macro-cell is reused by the femto-cell. Femto-cells maintain an exclusive list of user equipments (UEs) that they serve. In this case, a foreign macro UE trapped inside a femto-cell experiences heavy...
Coordinated Multi-Point (CoMP) concepts such as multi-cell joint detection and transmission, promising large improvements in spectral efficiency and fairness, appears to be an effective option to combat inter-cell interference in mobile communications. One major drawback of uplink joint detection is the large additional backhaul required when compared to a non-cooperative system. Theoretical work...
Heterogeneous cellular networks (HetNets) - conventional macro base stations overlaid with low-power nodes-are being deployed for reasons of improved spectral efficiency, economy, and scalable network expansion. To optimally realize the benefits of HetNets, it is crucial to factor deployment aspects such as cell association, transmission power, spectrum allocation, and deployment density. This paper...
The femtocell deployment in 3GPP/LTE sets new challenges to interference mitigation techniques and Radio Resource Management (RRM). Traditional schemes are mainly designed for classical cellular networks while the ad hoc nature of femtocells notably limits the complexity of possible algorithms. Thus, efficient RRM schemes are essential for limiting the interference impact on end-user performance....
In this paper we focus on finding a suitable Link Adaptation (LA) algorithm which is implemented as Channel Quality Indicator (CQI) selection technique in the 3GPP Long Term Evolution (LTE) system. The potential of Link Adaptation in the LTE system is not fully exploited. Therefore in our study, we compare the performances from different LA algorithms in the LTE system. The presented LA algorithms...
Multi-mode mobile equipments requires efficient radio-frequency (RF) filtering solutions to solve interference problems in a UMTS system integrated with a mobile television function. We designed and fabricated a pair of RF filters consisting of a band-pass and a band-stop filter, based on temperature-stable bulk acoustic wave resonator (BAW) technology. Both filters measurably demonstrate low insertion...
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