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In this paper we analyze various user assignment and scheduling policies for neigbouring femtocell networks. The trade-off between capacity maximization and fairness is investigated and a combined user assignment and proportional fair (PF) scheduling procedure for a femtocell gateway is proposed. The flexibility of the proposed architecture in terms of capacity and fairness is studied via various...
In this paper, we analyze the interference distribution and gain of beamforming in closed access femtocells in downlink of a two-tier HSDPA cellular network. We show through simulations that indoor femtocell deployment leads to a dominant interferer scenario. According to results even simple null steering method based on the scarce codebook of HSDPA transmit diversity mode 1 can be beneficially applied...
We report on field trials using CoMP transmission in the downlink of a mobile radio network. Two new features enable over-the-air CoMP transmission from physically separated base stations and terminals. These are distributed synchronization and a fast virtual local area network. Using VLAN tags, terminals feed back the multi-cell channel state information to their serving bases where it is multiplexed...
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...
This paper proposes a number of novel uses for 3D location and environmental geometry information to enhance the performance of the wireless physical layer. In the context of this paper, such information is obtained in real-time from a mobile operative carrying the ViewNet system. A location-based multi-user scheduler is proposed to exploit multi-user diversity by choosing users with wide angular...
In orthogonal frequency division multiple access (OFDMA) systems, efficient resource allocation is very important to improve the performance of the OFDMA system. The general principle of resource allocation in an OFDMA system is to assign each subcarrier to the user with the best channel condition for that subcarrier. However, in delay tolerant traffic, current work did not consider that packets on...
This paper deals with the blind source separation (BSS) problem in the overdetermined case, i.e. the number of receive antennas is larger than that of sources. First, a method, which converts the over-determined BSS into complete BSS, is presented. Then a maximum ratio combining (MRC) based BSS algorithm (MRC-FastICA) is proposed. The proposed algorithm includes source separation, estimated signals...
Exact average capacity results for L-branch coherent equal-gain combining (EGC) in correlated and uncorrelated fading channels are not known. This paper develops a novel framework (approach) for capacity analysis of L-branch EGC in generalized fading channels. In addition, Gamma shadowed generalized Nakagami-m fading model is proposed in order to statistically model the fading environments in high...
This paper analyzes the end-to-end performance of the cooperative diversity wireless networks using the amplify-and-forward relaying and the selection combining receiver over independent Rayleigh fading channels. The performance analysis is presented in terms of the outage probability and the average bit error rate. Since it is hard to find exact closed form expressions for the outage probability...
In this paper we focus on compressive sampling (CS) based ultra wideband (UWB) differential detection. We formulate an optimization problem to jointly recover the sparse received UWB signals as well as the differentially encoded data symbol. We utilize an alternating direction method of multipliers (ADMoM) to solve this joint optimization problem. Our proposed joint recovery method outperforms the...
Energy consumption of mobile access networks has recently received increased attention. Although cellular networks account for a rather small share of energy that is used by the ICT (Information and Communication Technology) sector, lowering their energy consumption appears important from an economical perspective. This paper recalls different means to enhance the capacity of evolved mobile networks...
Amplify-and-forward (AF) is one of the most popular and simple approaches to transmit information over a cooperative multi-input multi-output (MIMO) relay channel. In this paper, we propose three novel power allocation methods for the downlink of cooperative multi-user MIMO AF system, which are designed to maximize the weighted sum-rate (WSR) of the cooperative system, by considering two different...
The throughput of conventional wireless multicast systems is limited by the multicast user with the lowest channel quality, which leads to a very low throughput especially if the number of users is large. In this paper, we show that hybrid-automatic repeat request with Chase combining (HARQ-CC) is a promising technique to overcome this problem and optimize the transmission rate of wireless multicast...
Fractional frequency reuse for the downlink of multicellular WiMAX networks is examined in this work. Three different schemes are evaluated through simulations, including distance-based and SINR-based approaches, as well as a new scheme which is based on load-balancing between different reuse regions. The proposed load-balancing scheme overcomes the main weakness of the SINR-based approach, namely...
We have already proposed a hybrid single-carrier (SC) and multi-carrier (MC) system for next-generation mobile communication system. A SC signal has low peak-to-average power ratio (PAPR), which yields high power output for wide coverage. A MC signal is robust against frequency-selective fading and has high data rate with quadrature amplitude modulation (QAM). By appropriately selecting SC and MC...
In wireless dual-hop decode-and-forward (DF) relaying networks, multiple relay stations (RS) and users construct a multiple-in-multiple-out (MIMO) broadcast channel (BC). Due to unpredictable decoding failure, scheduling the transmission for the decode-and-forward broadcast channel (DFBC) should depend on not only channel qualities but also the availability of errorless data at individual RSs. Based...
This paper addresses the problem of transmitting data to multiple mobile stations using a decode-and-forward strategy. Precoding vectors are used in relays to cancel out multiple access interference at the mobile stations. Statistical distribution of signal to noise ratio (SNR) is approximated by an expectation maximization algorithm. Based on this distribution, system performance is evaluated for...
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...
In order to overcome the indoor coverage problem for residential users, the deployment of home base stations (also referred as home-eNB) has been regarded as a promising solution. However, the unpredictable deployment pattern of home-eNBs makes centralized network planning impractical and requires distributed spectrum planning to achieve effective interference management. In this paper, by enabling...
In this paper, we evaluate the delay experienced by Poisson arriving packets for Cooperative truncated HARQ with opportunistic relaying in the presence of a noisy feedback channel. We derive the theoretical expressions of the expected waiting time and the packet's sojourn time in the queue of truncated opportunistic cooperativeARQ and Hybrid ARQ I, with and without Packet Combining (PC), and Hybrid...
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