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In wideband sensing receivers, especially in low-cost mass-product devices, the sensing operation is usually done in a range where the RF front-end components, such as the LNAs exhibit a nonlinear behavior. Consequently, intermodulation (IMD) and crossmodulation (XM) are generated and cause distortion in the spectrum sensing region. This paper investigates the impact on the threshold level setting...
This paper investigates a Full-Duplex transceiver using an active cancellation technique where an additional transmit chain is employed to create the self-interference cancellation signal. Both transmitters and also the receiver are impaired by frequency-dependent I/Q imbalance with different parameters. It is shown how an I/Q parameter deviation in these chains deteriorates the achievable self-interference...
The performances of spatial array processing algorithms along with three-dimensional (3D) antenna arrays are studied in this paper. Optimal linear beamforming is compared to codebook based processing. The elevation domain is further utilized when applying separate weighting vectors for the azimuth and elevation dimensions. The theoretical capacities of the beamforming systems with different antenna...
Improved spectral and energy efficiency are two key requirements for the fifth generation (5G) wireless communication systems. The inefficiency and non-linearity of traditional power amplifiers (PA) pose significant challenges to meet these requirements, especially for multicarrier modulation signals (MCM) with high peak to average power ratio (PAPR). In this paper, we study methods to improve the...
This paper presents a transceiver prototype capable of in-band full duplex communication. Apart from a conventional transceiver and antenna, this prototype relies on a tunable electrical balance duplexer to minimize the in-band self-interference at RF. Such duplexer however requires continuous-time tuning to ensure accurate impedance balancing with the antenna across different environmental conditions...
We consider the application of linear physical layer network coding to next generation radio access networks (LPNC-RAN). We introduce a linear physical layer network coding scheme based on binary matrices, and illustrate its application to a simple example network topology. We compare this to benchmark schemes based on coordinated multipoint (CoMP), and show that while its performance is poorer than...
This work analyzes a heterogeneous network (HetNet), which comprises a macro base station (BS) equipped with a large number of antennas and an overlaid dense tier of small cell access points (SCAs) using a wireless backhaul for data traffic. The static and low mobility user equipments (UEs) are associated with the SCAs while those with medium-to-high mobility are served by the macro BS. A reverse...
Anticipating multimedia file requests via caching at the small cell base stations (SBSs) has emerged as a promising technique for enhancing the quality-of-service (QoS) of cellular user equipments (UEs). Nevertheless, in traditional caching approaches, files are retrieved from evolved packet core (EPC) of the network, and without coordination among SBSs, which introduces new challenges of content...
The millimeter-wave band is a candidate to overcome the spectrum shortage in future mobile radio networks. As the coverage area of base stations operating at these frequencies is expected to be more limited than at the sub 6 GHz bands, they will supplement existing base stations instead of replacing them. With these additional small cells a split plane architecture becomes an interesting architectural...
The surge of mobile broadband Internet access has nowadays reached the critical point that traffic is projected to increase dramatically in the next years and even the 4G UMTS Long term Evolution (LTE) cellular technology and its advanced version LTE-A might lack enough flexibility and system reconfiguration capability. For these reasons, the quest for the Fifth Generation (5G) of cellular technology...
Wireless 5G systems will not only be “4G, but faster”. One of the novel features discussed in relation to 5G is Ultra-Reliable Communication (URC), an operation mode not present in today's wireless systems. URC refers to provision of certain level of communication service almost 100 % of the time. Example URC applications include reliable cloud connectivity, critical connections for industrial automation...
In this paper, we investigate the use of a transfer learning approach applied to a topology management framework in a 5G heterogeneous aerial-terrestrial broadband access network, to reduce energy consumption and deployment cost, and improve system capacity and QoS. We implement a cognitive engine at the base station (BS), with reinforcement learning algorithms applied at the link level for spectrum...
Energy saving is an increasing trend in wireless communications development activities. This paper investigates how historic traffic load data can be used to estimate and set the load threshold used for switching on or off base stations or their features on a particular weekday. The use is enhanced by an abnormal day detection feature that is used to prevent undesired power on/off actions on days...
In this article, we provide an overview of the 5GETLA radio interface proposal for low latency dense small-cell networks. We discuss the new physical layer parametrization and frame design to support high energy and spectral efficiency in wireless small-cell communications and compare the main parameters with another recent physical layer design proposed for 5G centimeter wave communications. The...
Prolonging the battery life of mobile terminals (MTs) is critical for mobile users, especially for the smartphone users to enjoy the high data rate services offered by the future wireless networks. A collaborative mobile cloud (CMC), which consists of several MTs offers one potential solution for reducing the energy consumption at the terminal side in the downlink. In addition, as RF signal can carry...
This paper presents the analysis of departure elevation angles for the urban microcell radio channel measurements at 2.3 GHz. The measurements were conducted with EB Propsound CS™ for 30 × 16 antenna configuration in Oulu city center, Finland. The transmitter (Tx) antenna heights of 5 m and 10 m were used. The Tx antenna elements were arranged in the plus shape and nine antenna elements were placed...
Enhanced antenna technologies will be key enabling factors in the development of 5th-generation (5G) systems that will achieve significant improvements in system capacity. This paper presents a practical performance evaluation of an active antenna system (AAS) that can lead to high-capacity gain with vertical sectorization (VS). Active antennas have flexible radiation pattern control for adapting...
This paper presents the results and analysis of diffraction measurements around a building corner at 10 GHz. Radio channel measurement setup contains a 4-port vector network analyzer and two virtual antenna arrays. Angle of arrival analysis is carried out to distinguish the diffracted path from the other multipath components in the impulse response. Results are analyzed with respect to the Fresnel...
Since 5G expects using mmWave frequency band, the mmWave channel sounding system, which are used to characterise the various mmWave wireless channel models, these days, become a very hot topic for 5G.
In this paper, we investigate the outage probability for the mutual information of the sum rate for the MIMO (multiple input multiple output) MAC (multiple access channel) channel. We derive exact results for the “two users” case with two antennas and a general result for K users with an arbitrary number of antennas and different signal-to-noise ratios. As a secondary result, we derive an exact expression...
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