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Power control is one of the key functions which are able to co-ordinate the system interference. In this paper, several power control schemes are investigated for a hybrid LTE system, which combines the direct device-to-device (D2D) mode communication and the normal cellular mode communication. In the system study, the power control for the D2D mode communication is emphasized. In general, the utilization...
Inter-cell interference is a major problem in multi-cell OFDMA systems and can severely degrade the system throughput, particularly for cell-edge users. An efficient technique to mitigate inter-cell interference (ICI), is interference coordination that allocates certain resources among users in different cells. In this paper, we propose a novel and distributed algorithm in order to mitigate the inter-cell...
Long Term Evolution (LTE) is the latest step towards the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the possibility to transmit Multimedia Broadcast multicast service over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted...
This paper considers the use of predefined frequency-domain power profiles in downlink LTE-A aiming at making interference predictable across the Physical Resource Blocks, to be combined with fair resource allocation. In particular, the power profile structure is defined depending on the position of the users and fairness-oriented scheduling strategies are considered. Evaluations of the throughput...
The Physical Downlink Control Channel (PDCCH) is used to signal dynamic resource assignment information in the Long Term Evolution (LTE) system. In the presence of numerous active users, the system performance is likely to be hindered by shortage of control channel resource. In this paper, several simple algorithms are brought forward for making efficient PDCCH resource allocation. We first propose...
This paper focuses on the performance evaluation of LTE uplink in presence of bursty data traffic. First, the performance of different power control (PC) strategies in different load conditions is evaluated. It is shown that the optimal PV policy depends on the load in the network and/or in the own cell. Simulation results demonstrate that in low load conditions applying no PC (or alternatively using...
Careful management of inter-cell interference is important in OFDMA based systems such as LTE. In this paper, we study an uplink ICIC (Inter-cell Interference Coordination) mechanism, which fully utilizes the flexibility of frequency selective scheduling and rate adaptation, while dynamically limiting the interference experienced by the neighboring cells. This technique can be seen as an extension...
In cellular OFDMA networks, there exists a fundamental trade-off between the achievable cell capacity and the degree of fairness among the users in the cell. Several scheduling algorithms have been proposed which try to balance this tradeoff. The parameterization of these scheduling algorithms to achieve a certain desired fairness level is non-trivial. We show that the optimal fairness parameter settings...
The capacity and coverage area of a cell may vary due to changed environment, insertion or deletion of base stations, or malfunctioning base stations, and wrong parameter selection in the network planning phase. Suboptimal capacity and coverage area leads to the waste of network resources and the lower quality. Reacting on the changed situation manually is very expensive and time consuming. Therefore,...
In this paper we investigate the deployment of LTE indoor femtocells on the frequency band currently used by GSM cellular network. We consider a scenario where the LTE femtocells share GSM uplink spectrum provided that the legacy GSM users are not harmed by interference from the femtocells. Difference in the characteristics of GSM and LTE technologies is exploited to enable the spectrum sharing. The...
In current cellular networks base stations (BSs) usually perform independent scheduling without coordinating the resource allocation among different cells. This, however, often leads to high interference levels in cellular networks operating with universal frequency reuse, such as the 3GPP UTRAN Long Term Evolution (LTE). Coordinated scheduling between different BSs may mitigate this problem by taking...
Inter-cell interference coordination (ICIC) is one of the key technologies in the multi-cell radio resource management of mobile systems. It plays a vital role in mitigating strong inter cell interference and guaranteeing proper quality of services for in-progress sessions. Because heterogeneous deployment is adopted in LTE-Advanced, and interference problem becomes serious. In this paper, we propose...
Along with LTE-Advanced system and standardization investigation progress, the requirement for verifying relevant key technologies become more and more urgent. This article summarizes the progress of Huawei 4G Test-bed “HEART” (Huawei Experimental Advanced Radio Test-bed). CoMP technology is considered as a launch point to build up this test-bed competence. Some initial analysis and results are addressed...
Troubleshooting of wireless networks is a challenging network management task. We have developed, in a previous work, a new troubleshooting methodology, which we named Statistical Learning Automated Healing (SLAH). This methodology uses statistical learning, in particular logistic regression, to extract the functional relationships between the noisy Key Performance Indicators (KPIs) and Radio Resource...
Cooperative multi point transmission (CoMP) is the topic of different investigations regarding LTE-advanced networks to fulfill future capacity requirements by mitigating inter cell interference. If joint transmission is performed by several sectors to their assigned UEs, the interference within this cooperation area (CA) is suppressed completely, but still existent between different CAs. An user...
It has been recognized that a primary method of further enhancing the spectral efficiency of LTE Release-8 is to improve support for multi-user (MU) MIMO transmission in the downlink in an efficient manner. This paper investigates the performance improvements due to the enhanced support of single-cell MU-MIMO within the framework of LTE evolution (specifically LTE Release-9 and Release-10 also known...
In this article we have studied the coverage optimization for 3G Long Term Evolution (LTE) according to Minimization of Drive Tests (MDT) work item description in Third Generation Partnership Project (3GPP). Target for the MDT work item is to define a set of measurements and measurement reporting procedures, so that operators are able to collect measurement data from users and thereby reducing need...
Current cellular systems suffer from co-channel interference, when simultaneous transmissions in other cells use the same physical resources. Schemes involving cooperation between Base Stations (BS) are currently discussed for further releases of the 3GPP Long Term Evolution (LTE) system as a promising method to mitigate co-channel interference for users located at cell-edge. The BS cooperation approach...
In this paper the performance of multiple-input multiple-output (MIMO) system in the UTRAN Long Term Evolution (LTE) standard is evaluated by means of ergodic system capacity in low (3 km/h), medium (30 km/h) and high (120 km/h) mobility scenarios. The impact of adaptive modulation as well as Hybrid ARQ (HARQ) with Chase Combining to the distribution of effective SINR is established analytically and...
This paper proposes suboptimal precoding vector (PV) selection schemes combined with frequency domain scheduling when closed-loop MIMO precoding is adopted in the LTE (Long-Term Evolution)-Advanced uplink based on single carrier-frequency division multiple access (SC-FDMA) radio access. In the proposed schemes, frequency domain channel-dependent scheduling is performed based on a tentatively selected...
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