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We built up a Long Term Evolution (LTE) trial system operating in 5.8 GHz unlicensed bands and conducted a real time field trial in typical indoor environments. The user throughput of LTE with the 20MHz carrier in the unlicensed bands, which is used as a Supplemental Downlink (SDL) (always downlink), is evaluated and compared with that of Wireless Local Area Network (WLAN) with the same bandwidth...
This paper considers a multi-pair two-way relaying network, where multiple pairs of full-duplex users are served via a full-duplex relay with large-scale antennas under the amplify-and-forward protocol. Based on maximum-ratio combining/maximum-ratio transmission (MRC/MRT) processing, an exact achievable rate expression is derived by utilizing the statistical distribution of the channels to detect...
The use of Active Antenna Systems (AAS) in mobile communications has a number of advantages; the transmitted signal is focused, which results in a reduction of power required per connection, and the interference towards other users can be reduced, so the capacity of the system can be increased. One of the questions which arise in designing an AAS, is how to properly determine the current excitations...
Joint processing coordinated multipoint (JP-CoMP) is a new technology in LTE-A adopted to enhance the throughput of cell edge users as well as to mitigate interference. Relay Nodes (RNs) have also proven useful toward the realization of LTE-A, in improving the signal quality for the cell edge users. In this paper, we propose to combine JP-CoMP and relaying techniques for further improvements at the...
The existing literature about broadband satellite communications clearly indicates the exploitation of Extremely High Frequency (EHF) bandwidth portions and the massive employment of multi-beam satellites as key enabling technologies for “terabit connectivity” in the Space. In particular, increasing the reuse factor of frequency sub-bands, it is possible to boost multi-beam satellite capacity, provided...
In this paper, we consider a heterogeneous cognitive radio (CR) system where a large number of secondary users (SUs), having different path losses, can share the spectrum with a primary user (PU). We assume that the secondary base station (SBS) has an imperfect channel state information (CSI) of the interference channel between the SBS and the PU and does not have the full CSI from SUs. We consider...
Large-scale multiple input multiple output (MIMO) has a high spectral and energy efficiency and is considered as the promising technique for future 5G wireless communications. In practice, the accurate knowledge of channel state information (CSI) is of great importance to guarantee the performance of MIMO systems. However, the conventional training sequence (TS) based approaches usually suffer from...
The paper analyzes the stability issue of a special emulator of memristive, memcapacitive and meminductive systems as well as higher-order elements from Chua's periodical table, and other two-terminal devices. It is demonstrated that, in order to provide stable behavior, the analog port of the emulator must be implemented by the controlled voltage or current source depending on the type of the emulated...
Three types of antenna arrays such as uniform linear, uniform rectangular arrays and uniform cube arrays are used in the transmitter and their corresponding channel capacity on several paths in the indoor environment are calculated. Numerical results show that uniform linear arrays is better than that for uniform rectangular arrays and uniform cube arrays system with and without interference.
The underlay cognitive radio that allows an unlicensed user to access the spectrum owned by the primary user even during its transmission but under tight interference constraint that protects the primary user which in the contrary affects the performance of the secondary one, is a very challenging investigation. We reduce the symbol error probability by improving the performance of the instantaneous...
The underlay cognitive radio that allows an unlicensed user to access the spectrum owned by the primary user even during its transmission but under tight interference constraint that protects the primary user which in the contrary affects the performance of the secondary one, is a very challenging investigation. Benefiting from antenna selection spatial diversity technique, we develop the instantaneous...
In this paper, we analyze the performance of a dense small cell network with multi-antenna Base Station (BS)s employing spatial Poisson Point Process (PPP) model. In this model, the BSs and User Equipment (UE)s are distributed as two independent PPPs which are well appropriate for upcoming small cells in the next generation of wireless systems. We consider the scenario in which the small cell BSs...
In this work, we consider cloud RAN architecture and focus on the downlink of an antenna domain (AD) exposed to external interference from neighboring ADs. With system sum-rate as performance metric, and assuming that perfect channel state information is available at the aggregation node (AN), we implement i) a greedy user association algorithm, and ii) a greedy remote radio-head (RRH) clustering...
Ultra-reliable communications over wireless will open the possibility for a wide range of novel use cases and applications. In cellular networks, achieving reliable communication is challenging due to many factors, particularly the fading of the desired signal and the interference. In this regard, we investigate the potential of several techniques to combat these main threats. The analysis shows that...
During the past decade, Molecular Biology wet labs and sequencing activities have been generating a vast amount of data, causing an increase in the adoption of new methods and tools for identification and analysis. In particular, the use of software agent technology in bioinformatics applications has been on the rise, due some of its unique features as autonomy and remote execution capabilities. However,...
Cognitive radio (CR) and spatial modulation (SM) are two exciting and emerging techniques to increase the spectrum efficiency for 5G. In this paper, we present a novel cooperative spectrum sharing protocol using SM. A two phases uncoded decode-and-forward (UDF) relaying scheme is considered. A secondary transmitter (ST) consisting of Mt transmit antennas act as UDF relay for the primary system (PS)...
Massive multiple-input multiple-output (MIMO) in time-division duplexing (TDD) systems relies on the channel reciprocity to obtain the downlink (DL) channel state information (CSI) with the uplink (UL) CSI. But in practice, the transmit branch is composed of different radio frequency (RF) circuits from the receive branch, which breaks the end-to-end DL/UL channel reciprocity. Antenna array calibration...
This paper will design a resource allocation algorithm, mainly on downlink transmission by Base Station (BS) to User Equipments (UEs) implemented using directional antenna. The resource allocation is accomplished by Pair-Wisely Bottom-Up (PWBU) approach, targeting a time-efficient allocation based on SINR feedbacks. We utilize adaptive smart antennas capable of simultaneous transmission toward different...
Experimental investigations by have been done to understand co-channel interference characteristics between the small cells installed in indoor environments. However, there are a lot of complex situations in the arrangement of indoor small cells, so that it seems to be hard to build the general interference modeling through experimental results due to strong dependences on the environmental conditions...
In order to optimize the use of the frequency spectrum is often performed frequency sharing between two or more service providers. The Government of Indonesia through PERMENKOMINFO number 25 in 2014 allow the use of frequency sharing between the Fixed Satellite Service and Fixed Service in extended C-Band frequency. Frequency sharing conditions can lead to potential interference so both services need...
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