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In future B3G/4G communication systems, the special application of femtocell in the enterprise offices and public places has broad prospect. However, as the femtocell operation under such multi-femtocell environment is significantly different from that of usual residential femtocells, the femtocell configuration and optimization might be much more complex. One key issue is to find how will the femtocell...
To explore the benefit of Coordinated Multiple Point transmission/reception (CoMP) will reduce the exchange overhead between the cells, a distributed Rubinstein-Stahl Bargaining based Power Allocation (DBPA) scheme is proposed in this paper. The introduced scheme can provide a possible solution to share the increased benefits, which are obtained at a serving cell when a slaving cell joins to coordinated...
In this work a strategy for triggering an interradio access technology cell reselection in UMTS user equipment is proposed. All mobile devices within the effective range of a transmitter radiating a noise-like RF signal on the UMTS downlink frequency bands are forced to leave the UMTS cells and camp on non-UMTS cells, such as e.g., GSM. This allows to use a GSM based localization technique even in...
Femtocells applied in many existing systems, such as HSPA, 3GPP LTE, WiMAX, and etc, which cover a short range and offer an economically viable way to improve cellular system capacity, have caught world-wide researching interest nowadays. The primary purpose of femtocell solutions has been to improve indoor coverage in current cellular systems. Here, users that are moved to femtocells experience increased...
Carrier aggregation in LTE-Advanced provides the capability to uncoordinatedly deploy home eNodeBs with the opportunity to autonomously mitigate the interferences. Among many improvement approaches, the autonomous component carrier selection (ACCS) scheme to improve the performance of the cell edge users worth our attentions. However, a poorly ordered execution of the carrier selection can lead to...
The IMT-2000 standard UMTS of (Universal Mobile Telecommunications System) is based on Wideband CDMA (Code Division Multiple Access). To access a shared transmission channel for multiple users, UMTS exploit Code Division Multiple Access (CDMA). Multi-user interference is a critical issue in CDMA, limited user, cell Capacity and limiting spectral efficiency dramatically. The manner of used multiple...
Inter-cell interference (ICI) is responsible for user throughput degradation and especially for users found near cell border which additionally experience serious path-losses. Efficient methods for ICI mitigation are ICI coordination (ICIC) schemes which allocate certain resources among users in different cells. In this paper we propose a decentralized ICIC scheme in order to mitigate the ICI and...
This article presents a summary of 3GPP Long Term Evolution (LTE) radio system performance during the execution of a multi-site field trial. This exhaustive testing campaign, performed over the lower 700 MHz and 2 GHz bands, includes a battery of stationary and mobility throughput cases, multi-user capacity scenarios, handover performance and latency tests, that have been designed to reveal LTE radio...
Distributed antenna system (DAS) constitutes one of the most fascinating schemes to efficiently achieve the rigorous quality of service demands of next generation wireless networks. System level simulation (SLS) approach is considered since things are too complicated to be dealt only analytically and it would not be cost-effective to deploy all the real scenario to test every feature.In this paper,...
We consider wireless femtocell networks where scheduling of transmissions is coordinated across multiple cells to mitigate interference and deliver fairness and quality of service (QoS). Coordination across multiple cells entails (i) exchange of (serving and interfering) channel information and traffic priority (which is a function of packet delays, average rate, queue length), and (ii) signalling...
We design novel mechanisms and algorithms for fast, simple, and distributed interference management and scheduling in wireless femto networks via exchange of information over-the-air (OTA). We focus on Long Term Evolution (LTE) of the 3GPP standard and on the downlink; we leverage the existing signalling in LTE and delineate additional signals that are needed. Key aspects of our work include: (1)...
In this paper we look at the diversity of equal gain transmission (EGT) for single user (SU) MIMO and multiuser (MU) MIMO in the context of third generation partnership project long term evolution (3GPP LTE). We look at the low resolution LTE precoders which are based on the principle of EGT. Our analytical results show that EGT has full diversity in SU MIMO while the simulation results show that...
We address the coexistence problem between macrocell and femtocell systems by controlling the aggregated interference generated by multiple femtocell base stations at the macrocell receivers in a distributed fashion. We propose a solution based on intelligent and self-organized femtocells implementing a realtime multi-agent reinforcement learning technique, known as decentralized Q- learning. We compare...
In UMTS cellular networks, Common Pilot Channel (CPICH) signals are broadcast by base stations for channel estimation and cell selection. The strength of CPICH signal determines cell coverage and pilot pollution to neighboring cells; pilot power allocation thus involves a tradeoff between coverage and interference. In this paper, we study the issue of pilot power management in closed-access High-Speed...
Multiple Input Multiple Output (MIMO) transmission improves downlink spectral efficiency and is a key feature of Release 7 High Speed Downlink Packet Access (HSDPA). When the Node-B is configured in the MIMO mode with secondary common control pilot channel (S-CPICH), the power amplifiers (PAs) for the two transmit antennas are not balanced. A common pre-coder is required to balance the PAs for legacy...
3GPP has recently approved a new work item for LTE-A to support enhanced inter-cell interference coordination (eICIC) for co-channel deployments of heterogeneous networks. The main focus is on the coordination of control and data channel interference between macro and low power nodes, e.g., relay, pico, and femto. Since the femto cells are randomly deployed by consumers with closed access and X2 interface...
Femtocells are envisioned to be deployed in indoor environments in order to improve both radio coverage and system capacity. This paper focuses on the self-organization of enterprise femtocells, which is certainly more challenging than that of home femtocells. In the context of 3GPP LTE, we propose solutions to automatically tune parameters such as radio spectrum, pilot power, resource blocks, and...
With the active evolvement of 3GPP long term evolution (LTE) system, advanced multi-user multiple-input multiple-output (MU-MIMO) transmission schemes attract more and more interests in engineering field. However, in order to bring advanced MU-MIMO techniques from theory to practice, there are two major obstacles to overcome, i.e., how to obtain accurate channel state information at the transmitter...
TD-SCDMA is one of the third generation (3G) mobile communication standards, which is coming into the commercial phase. Along with the network deployment, planning and optimization tools are playing an important role to ensure the network performance. Scanner is one of the important tools, contributing to optimize the wireless network performance via drive test, tower site survey, in-building measurement,...
In this paper, we propose a SINR(Signal to Interference plus Noise Ratio), AHP(Analytic Hierarchy Process) and information Entropy weight method based TOPSIS (SAE-TOPSIS) vertical handoff algorithm which uses the combined effects of SINR with SINR value from one network being converted to equivalent SINR value to the target network for getting the same data rate, user required bandwidth, user traffic...
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