On the optimisation of practical wireless indoor and outdoor microcells subject to QOS constraints

Wireless indoor and outdoor microcells (WIOMs) have emerged as a promising means to deal with a high demand of mobile users for a variety of services. Over such heterogeneous networks, the deployment of WIOMs costs mobile/telecommunications company high capital expenditures and operating expenses. This paper aims at optimising the WIOMs taking into account various network communication environments. We first develop an optimisation problem to minimise the number of cells as well as determining their optimal locations subject to the constraints of the coverage and quality-of-service (QoS) requirements. In particular, we propose a binary-search based cell positioning (BSCP) algorithm to find the optimal number of cells given a preset candidate antenna positions. The proposed BSCP algorithm is shown to not only reduce the number of cells for saving resources but also requires a low computational complexity compared to the conventional approaches with exhaustive search over all available sites. Moreover, EDX SignalPro is exploited as a simulation platform to verify the effectiveness of the proposed BSCP for the WIOMs with respect to various propagation modes and antenna parameters of different types, including isotropic, multiple-input single-output and multiple-input multiple-output

On the resource allocation for D2D underlaying uplink cellular networks

Device-to-Device (D2D) communications has attracted research interests as an emerging technology towards 5G and beyond cellular networks. In this paper, we investigate the power allocation in D2D underlaying cellular networks with uplink channel reuse. We first develop an optimization problem to minimize the total power consumption subject to per- user Quality-of-Service (QoS) constraints. A distributed power allocation algorithm is proposed to allocate the power for both D2D and cellular users by exploiting the property of strictly non-negative inverse of a Z-matrix. It is shown that the power allocated for users can be considerably saved for low QoS requirements, especially with a large number of D2D users. The proposed algorithm is validated through simulation to realize the impacts of noise power, distance between D2D users and the number of D2D pairs in the network

An optimal power allocation for D2D communications over multi-user cellular uplink channels

Device-to-Device (D2D) communications has emerged as a promising technology for optimizing spectral efficiency, reducing latency, improving data rate and increasing system capacity in cellular networks. Power allocation in D2D communication to maintain Quality-of-Service (QoS) remains as a challenging task. In this paper, we investigate the power allocation in D2D underlaying cellular networks with multi-user cellular uplink channel reuse. Specifically, this paper aims at minimizing the total transmit power of D2D users and cellular users (CUs) sub- ject to QoS requirement at each user in terms of the required signal-to- interference-plus-noise ratio (SINR) at D2D users and base station (BS) over uplink channel as well as their limited transmit power. We first derive expressions of SINR at the D2D users and BS based on which an optimization framework for power allocation is developed. We then propose an optimal power allocation algorithm for all D2D users and CUs by taking into account the property of non-negative inverse of a Z- matrix. The proposed algorithm is validated through simulation results which show the impacts of noise power, distance between D2D users, the number of D2D pairs and the number of CUs on the power allocation in the D2D underlaying cellular networks

Soil Geochemical Survey of Eruku and Environs

The study area, Eruku and its environs, is located approximately 124km east of Ilorin and lies within Osi migmatite gneiss complex to the west and Egbe schist belt in the east. The area falls within longitudes 5023’E and 5030’E and latitudes 8005’N and 8013’N represented in Osi sheet 224SE . Detailed mapping and sampling of rocks and soils were carried out in this area. The soil samples were collected from the B horizon at a depth of 20cm-25cm. Twenty-five selected soil samples were analyzed for trace and rare earth elemental concentration using ICP, INAA, MS and ICP-MS analytical methods. The result of the geochemical analysis was thereafter subjected to statistical analysis and isograde plotting. The multivariate statistical analysis shows a total of eleven factor groups. Seven of the factor groups are of importance in the study area with five related to mineralization. The correlation coefficients of some selected elements show that Be is strongly correlated with Rb, Ga, Sn and Ta while Nb is strongly correlated with Ta. The area and bar charts show that the highest concentrations of Be, Nb, Sn and Ta are in the northeastern part of the study area. The isograde plots show that almost all the elements have their peaks in the northeastern part of the study area. From the integration of geochemical and multivariate analyses, and isograde plotting, the study area has anomalous concentration of cassiterite-tantalite-columbite minerals. These mineralizations are hosted by pegmatites that intrude the country rocks in the study area. This establishes similarity in terms of host rocks and mineralization type of the Eruku area compared to Egbe. Keywords: Mineralization, soils, geochemical data, cluster groups, isograde plotting, Eruku