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In this paper, we propose a robust Grassmannian prediction algorithm to provide channel state information (CSI) at the base station for multiuser multiple-input multiple-output (MIMO) systems with delayed limited feedback. The underlying coherence among adjacent quantized CSIs is fully exploited to achieve robustness against the quantization error caused by the limited feedback. Rather than sticking...
Base station cooperation in the downlink of cellular systems has been recently suggested as a promising concept towards a better exploitation of the communication system's physical resources. It may offer a high gain in capacity through interference mitigation. This however, comes at a cost of high information exchange between cooperating entities and a high computational burden. Clustering of base...
In this paper, we define a multi-access interference (MAI) cost that can assess the extra interference, inherent to relaying use and perceived by the whole cellular network. This MAI cost shadows an implicit and smart power control for CDMA uplink communications. In fact, this cost takes into account not only the reception quality required at the serving base station but also the global interference...
Given the growing concern over energy consumption and associated global warming, green communication is becoming more and more important. Lots of efforts have been put into investigating energy efficiency based design in wireless systems. Unfortunately, the maximum energy efficiency of a point-to-point link is normally achieved when the transmit power approaches zero, which, however, is not desirable...
In this paper, we consider 2D wireless multi-hop networks with mobile nodes randomly distributed on a torus, and a small number of base stations (infrastructure nodes) deterministically placed in the same area. Mobile nodes move following a random walk mobility model. A piece of information is broadcast from the base stations at the same time in a multi-hop manner using a Susceptible-Infectious-Recovered...
In conventional cognitive radio networks it is usually assumed that the primary network remains unchanged. The onus is then placed on the secondary network users to make the best use of any residual radio capacity. In some situations however, the primary network operator may wish to accommodate secondary user access. This objective has motivated recent work which considers simple modifications at...
Coordinated beamforming in multipoint MIMO networks has been introduced to increase the overall capacity of wireless networks. In coordinated beamforming, the channel state information between the different MIMO access points/base stations in one hand, and the mobile stations on the other hand, needs to be shared among the MIMO nodes. A “backhaul” between different MIMO access points is used to transfer...
We present a new co-operative scheduling approach which provides not only more reliability but also higher effective capacity. Cooperation region is defined for active handoff users between two base stations (BSs) based on the user quality-of-service (QoS) requirements. A proper definition of co-operation or handoff region, where the user can be scheduled in a cooperative manner from more than one...
In this paper we design a robust opportunistic scheduler to be implemented at the base station in a cellular network for broadcast media streaming applications. The scheduling mechanism operates based on information on both the average and the instantaneous user distributions, and on radio link channel quality, obtained through the cellular uplink channel. Video streams are encoded into multiple scalable...
The traffic demand in future mobile cellular networks is expected to increase exponentially which would lead to dense base station deployment and eventually higher energy consumption. The current dominant mobile systems including GSM and UMTS were not designed with focus on energy efficiency. This paper investigates the energy saving potential of pico nodes in a heterogeneous network from an incumbent...
The signalling subsystem is the most expensive and complex element in cellular networks. Today's networks use signalling mechanisms whose design builds on more than 20 years of the operational expertise. Despite this, the signalling subsystem of all mobile network standards remains vulnerable to failures of equipment and to sharp increases in offered load caused by unanticipated traffic patterns....
Joint power and rate control is a key element to the efficient use of wireless system resources especially when considering heterogeneous services with various transmission rates and requirements. Although several game-theoretic approaches have appeared to solve this problem their stable outcome is extracted independently or semi-jointly, and the corresponding equilibrium solutions introduce several...
An inter-cell interference (ICI) problem between co-channel BSs has been one of main challenging research issues in downlink cellular networks. Fractional frequency reuse (FFR) and BS cooperation are useful techniques to manage the ICI problem. By combining the BS cooperation and FFR techniques, we propose to determine an efficient cooperation mode and the type of subchannels, i.e., reusable subchannels...
An approach advocated in the recent literature for reducing energy consumption in cellular networks is to put base stations to sleep when traffic loads are low. However, several practical considerations are ignored in these studies. In this paper, we aim to raise questions on the feasibility and benefits of base station sleeping. Specifically we analyze the interference and capacity of a coverage-based...
We propose a new architecture for broadcasting an enormous amount of information over a large population of users in a typical urban area via multiple base stations for delay tolerant applications. The core idea is that each base station partially broadcasts the information instead of transmitting the whole information. In particular, the large target file is broken into M smaller chunks and is provided...
We consider how to efficiently employ D2D communications for secondary users (SUs) in a cognitive cellular network. In this network, primary users (PUs) transmit via base station normally, while SUs can employ multiple transmission modes. One is to transmit via base station (BS mode), and the other is to employ D2D communication (D2D mode) due to the scarce idle spectrum. The SUs who have the potential...
With the explosion of wireless communications in number of users and data rates, the reduction of network power consumption becomes more and more critical. This is especially true for base stations which represent a dominant share of the total power in cellular networks. In order to study power reduction techniques, a convenient power model is required, providing estimates of the power consumption...
Current point-to-multipoint systems suffer significant performance losses due to greater attenuation along the signal propagation path at higher frequencies, transmit power constraints of mobile users and base stations, and interference from neighboring cells. Fractional Frequency Reuse (FFR) is a technique to counteract these effects. Typically, the proposed FFR technique partitions a cell into a...
It is widely believed that cooperation among base stations can be employed to enhance the interference mitigation capability of base station receivers in cellular networks. Among the base station cooperation schemes that have been proposed to address the uplink interference problem, two promising ones are 1) Joint Multi-Cell MMSE Processing also referred to as Network MIMO; and 2) Multi-Cell Successive...
We propose a new network model framework, denoted heterogeneous fluid model network, which allows to derive closed formula for the Signal to Interference plus Noise Ratio (SINR) received by a mobile in heterogeneous cellular networks, composed of macro cells and femto cells. Quality of service (QoS) and performance of wireless networks can therefore be analyzed in a simple way. We apply our model...
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