Home Base Station Research Articles

Approaches and mechanisms for increasing capacity and internal building radio coverage of mobile cellular networks

The aim of the report is to study different approaches and mechanisms for increasing the capacity and internal building radio coverage of mobile cellular networks. Various methods for indoor radio coverage are presented by comparing and analyzing the proposed solutions. On the occasion of overcoming the limitation of external microcells, other differentiated approaches are proposed for direct increase of the internal building signal. The approach consists of implementing antennas and equipment directly inside the buildings. These indoor antennas and radio engineering is defined as a distributed antenna system. With the development of mobile cellular networks of the fourth 4G and the introduction of the fifth 5G generation increasingly began to rely on a new optimal and effective approach to improving internal radio coverage and capacity in buildings and premises of end users presented as home base stations or femtocells.

Research of femtocell technologies for mobile cellular networks

The purpose of writing this article is to present and study femtocellular technologies for mobile cellular networks. With the introduction of the fourth 4G-LTE and the fifth 5G generation of mobile cellular systems, the term femto cell began to be strongly mentioned. Femto cells are very small cells that provide mobile service users with a home base station to connect to the telecommunications operator's network. The femtocell technologies are mainly looking for ever higher data rates indoors, which most often leads to the implementation of UMTS / HSPA modules in the femtocell access point, as well as LTE and 5G.

A Novel Network Resolved and Mobile Assisted Cell Search Method for 5G Cellular Communication Systems

When the user equipment (UE) is turned on, it first needs to perform an initial cell search procedure before it can communicate with the base station (BS). However, this procedure must deal with the initial time and frequency synchronization and search for the appropriate home BS for services. In conventional cell search methods, the entire cell search process is carried out on the UE, where the computational requirement can lead to additional overhead and power consumption of the UE. Therefore, aiming to help UEs offloading their overhead to BSs, we in this paper propose a novel cell search method, called <i>Network Resolved and Mobile Assisted Cell Search</i>, which can achieve our goal by letting the BSs be the main performers for deciding the appropriate BSs for connection and letting UEs only be the assistants of the cell search process. The implementation details and analysis of the proposed cell search approach are provided along with the numerical simulations. Results show that our proposed cell search not only can offload the computational overhead, but it also outperforms the conventional code-based cell search approach in terms of the cell search error probability with similar overall network energy consumption.

Resource allocation and interference management for multi-layer wireless networks in heterogeneous cognitive networks

Aiming at the research of resource allocation and interference management in multi-layer wireless networks in heterogeneous cognitive networks, this paper mainly discusses the resource allocation and interference management in heterogeneous cognitive networks and proposes our proposed cluster-based cooperative interference management scheme. This scheme minimizes the cross-layer interference of multiple base station cells to primary users and avoids the same-layer interference between base station cells through joint channel allocation and power allocation. Through cognitive perception or joint scheduling, the available channel can be obtained by the home base station cell, and then the channel, power and other resources can be allocated according to the related algorithms proposed by us, so as to ensure the harmonious coexistence of the home base station cell and the authorization system such as macrocell. Finally, we validate the proposed algorithm. The simulation results show that the algorithms are effective in reducing interference, but the degree is different.

Uplink SINR Analysis in Massive MIMO Systems Using Ginibre Point Process

This paper deals with the coverage probability analysis of Massive MIMO networks with random topology. Poisson Point Process is a popular stochastic geometry approach for finding the location of nodes in a network. But in this model, the spatial correlations among the nodes are negligible; and hence this model is not realistic in nature. Also, this model is not suited for repulsion between the nodes that will perform. For repulsion between the nodes, Ginibre point process (GPP) is a determinant point process (DPP) proposed in this paper to model the network with repulsion considered as a realistic model. There are two centric approaches used in Massive MIMO Networks. One is Base station centric approach and another one is user centric approach. The use centric approach is preferred in this paper due to proper handling interference co-ordination based on the distance between home BS base station and interfering BS’s, the interference is reduced. By using this method, the critical interferences are eliminated and there is no cluster edge user used in this method. This method is known as user centric interference coordination. In base station centric approach, in interference management method, the base station (BS) is located at center which performs interference coordination and at the user at cluster edge suffers the severe interference. The closed form expression for coverage probability for uplink data transmission is derived using the GPP and user centric approach. Numerical and simulation results are analyzed and compared.

Probability Weighting Localization Algorithm Based on NLOS Identification in Wireless Network

In this paper, a localization scenario that the home base station (BS) measures time of arrival (TOA) and angle of arrival (AOA) while the neighboring BSs only measure TOA is investigated. In order to reduce the effect of non-line of sight (NLOS) propagation, the probability weighting localization algorithm based on NLOS identification is proposed. The proposed algorithm divides these range and angle measurements into different combinations. For each combination, a statistic whose distribution is chi-square in LOS propagation is constructed, and the corresponding theoretic threshold is derived to identify each combination whether it is LOS or NLOS propagation. Further, if those combinations are decided as LOS propagation, the corresponding probabilities are derived to weigh the accepted combinations. Simulation results demonstrate that our proposed algorithm can provide better performance than conventional algorithms in different NLOS environments. In addition, computational complexity of our proposed algorithm is analyzed and compared.

Design of Green Smart Room Using Fifth Generation Network Device Femtolet

Designing smart room with energy-efficient data and application offloading facilities for the users is a crucial issue. This paper has proposed the architecture of a self-organized smart room where the users can offload their data and applications at low power and low latency. Sensors and detectors are used to collect status of the objects present in the room and according to the collected information, the microcontroller operates other devices e.g. lights, AC, smoke detector etc. located inside the room in order to create a self-organized environment. In the proposed architecture fifth generation network device Femtolet is used as a small home base station with cloud environment. The proposed smart room architecture is implemented using network simulator Qualnet version 7 and its performance is evaluated with respect to energy consumption, carried load, delay, jitter and throughput. The simulation results show that Femtolet reduces the energy consumption and delay in accessing cloud services by approximately 14–57% and 8–35% respectively than the femtocell base station to build a green smart home environment.

C2OF2N: a low power cooperative code offloading method for femtolet-based fog network

Power and delay aware cloud service provisioning to mobile devices has become a promising domain today. This paper proposes and implements a cooperative offloading approach for indoor mobile cloud network. In the proposed work mobile devices register under femtolet which is a home base station with computation and data storage facilities. The resources of the mobile devices are collaborated in such a way that different mobile devices can execute different types of computations based on cooperative federation. The proposed offloading scheme is referred as cooperative code offloading in femtolet-based fog network. If none of the mobile device can execute the requested computation, then femtolet executes the computation. Use of femtolet provides the mobile devices voice call service as well as cloud service access. Femtolet is used as the fog device in our approach. The proposed model is simulated using Qualnet version 7. The simulation results demonstrate that the proposed scheme minimizes the energy by 15% and average delay up to 12% approximately than the existing scheme. Hence, the proposed model is referred as a low power offloading approach.

Overview on Interference Management Technology for Ultra-Dense Network

The explosive growth of the mobile traffic demand has triggered the investigation of 5th generation mobile networks (5G) for the future development of wireless communications. The ultra-dense network (UDN) has the ability to effectively improve system throughput and spectrum utilization by deploying a large number of low-power, low-cost, low-power home base stations or micro base stations. The dense distribution of micro base stations poses new challenges in terms of energy loss and interference management. Firstly, the overview of 5G is briefly introduced in this paper. Then, interference management method for UDN is summarized. So far, interference management methods for UDN mainly include interference alignment, clustering, and resource allocation. The principles of the three methods are described in detail. Finally, we conclude that clustering and resource allocation are more suitable for UDN.

Анализ системы нормирования на железнодорожном транспорте с позиций логистики и клиентоориентированности

Objective: The study of railroad transport rate-setting system from a position of customer-oriented approach and logistics, particularly the development of specific practical proposals of freight delivery system optimization and the assessment of OJSC “Russian Railways” logistic (terminal stocking) activity indices. Methods: Analytical method was applied, as well as economical and mathematical tools of terminalistics, being a new school. Results: An attempt was made to review the existing railway freight delivery system. It was observed that it was unreasonable to exclude materials handling elements - logistical objects (LO) of different types, from a logistical chain as by means of the element in question the freight arrives at as well as leaves the railroad. If the focus is made only on operating indices of functioning and traffic section of a logistical chain, it artificially impoverishes the strongest functional of railway enterprises, leading to a simplistic approach of traffic process managing and does not contribute to freight flow transferring to railroads. A new system of indicators was suggested for economic justification and calculation of parameters LO and TS, which were missing before. All indices were adjusted to the existing system of economical and operational indices of storage yard and railroads functioning. The new system may be applied in logistical rating, as well as terminal and stocking infrastructure of OJSC “Russian Railroads”. It may be used for: 1) LO identification; 2) LO selection taking into account its functionality, dislocation, etc. ; 3) construction projects’ assessment and reconstruction of terminal and stocking railroads’ infrastructure facilities; 4) logistical functioning of OJSC “Russian Railroads” holding company; 5) LO construction; 6) railroad transport functioning forecasting and planning. Practical importance: The application of the originally developed system of indicators will allow OJSC “Russian Railroads” to effectively design, operate and plan the functioning of terminal and stocking infrastructure facilities. The effectiveness of the suggested TSS is in more rapid freight delivery to consumers, expenditure reduction in technical maintenance and ineffective railway sidings and section’s stations repair, shunting and exporting train locomotives release, as well as passing siding of a section’s station for more effective formation of exit routes, technical and station’s speed increase of line haul main directions through home-base station, due to a number of train operation paths release, occupied with demountable export trains’ operation.

Resource Allocation Based on Channel Sensing and Spatial Spectrum Reuse for Cognitive Femtocells

A cognitive femtocell is a new small cell based on a smart home base station to solve the spectrum-scarcity problem. Recently, dedicated resource allocation for cognitive femtocell to mitigate co-channel interference is extensively researched. However, the cognitive femtocell may suffer from the lack of frequency resource for its users due to high data traffic load of the macrocell. We propose a novel resource allocation and power control mechanism using spatial frequency reuse and spectrum sensing, which enables femto users in the cognitive femtocell to obtain more feasible resource. We analyze and evaluate the performance gain of the proposed scheme. Although data traffic load of the macrocell increases, the capacity of the cognitive femtocell can be maintained appropriately by the proposed resource allocation and power control scheme and it is shown that the performance is improved compared to that of the conventional scheme.

Adaptive Service Rate and Vacation Length for Energy-Efficient HeNB Based on Queueing Analysis

To improve the energy efficiency of small-cell networks, in this paper, we analyze the operating procedure of home base stations, i.e., Home evolved Node B (HeNB), in femtocells, by introducing an MAP/PH/1/k queueing model. In this analytical model, the HeNB's power on/off is represented as the alternative service and vacation periods. In addition, the hybrid-access mode defined in Third-Generation Partnership Project (3GPP) Release 9 is considered, which involves both high-priority and low-priority users. Based on the analytical results, an adaptive service rate and vacation length (ASV) method is proposed to maximize the HeNB's energy efficiency while satisfying its quality-of-service (QoS) requirements, such as blocking probability and user waiting time. Simulation results demonstrate that the proposed ASV method is more effective in improving energy efficiency compared with its counterpart.

Coordinated Multicast Based on a MIMO Relay Station in a Single Frequency Network

In this paper, we present a coordinated multicast scheme via a relay station (RS) over a single frequency network (SFN). According to the type of feedback information delivered from the RS to the adjacent base stations (BSs) involved in the coordinated multicast, the schemes are classified into the phase coordination multicast based on the RS (PCMR) and the vector coordination multicast based on the RS (VCMR). For the performance analysis, we derive the mathematical upper bound of an achievable rate from the BSs to the RS for the coordinated multicast based on RS. Through this analysis, we demonstrate that the PCMR and the VCMR achieve more gains over the noncoordinated multicast in terms of the number of RS antennas, the number of adjacent BSs, and the number of BS antennas. Through simulation, we derive a range of distances between the home BS and the RS, the number of users, and the number of user antennas, providing evidence that the RS-based multicast outperforms the conventional multicast.

Computerised Analysis of Telemonitored Respiratory Sounds for Predicting Acute Exacerbations of COPD.

Chronic obstructive pulmonary disease (COPD) is one of the commonest causes of death in the world and poses a substantial burden on healthcare systems and patients’ quality of life. The largest component of the related healthcare costs is attributable to admissions due to acute exacerbation (AECOPD). The evidence that might support the effectiveness of the telemonitoring interventions in COPD is limited partially due to the lack of useful predictors for the early detection of AECOPD. Electronic stethoscopes and computerised analyses of respiratory sounds (CARS) techniques provide an opportunity for substantial improvement in the management of respiratory diseases. This exploratory study aimed to evaluate the feasibility of using: (a) a respiratory sensor embedded in a self-tailored housing for ageing users; (b) a telehealth framework; (c) CARS and (d) machine learning techniques for the remote early detection of the AECOPD. In a 6-month pilot study, 16 patients with COPD were equipped with a home base-station and a sensor to daily record their respiratory sounds. Principal component analysis (PCA) and a support vector machine (SVM) classifier was designed to predict AECOPD. 75.8% exacerbations were early detected with an average of 5 ± 1.9 days in advance at medical attention. The proposed method could provide support to patients, physicians and healthcare systems.

Correlation Phenomenon Versus Beam-Subset Scenario in MIMO-Femtocell System with Fading Environments

The channel correlation happens in a MIMO-femtocell (multiple-input multiple-output) system with beam-subset beamforming technique is investigated in this paper. MIMO-femtocell system constructed with MIMO signaling that is adapted to a tiered femtocellular network. The MIMO-femtocell system deployed with home base station (BS) in a single floor indoor environment is proposed. According to the analyses of both theoretical and simulation results, channel correlation definitely degrades the overall system performance of a MIMO-femtocell system with beam-subset, especially in indoor channels. Moreover, the coverage area of a MIMO-femtocell deployment is reduced because of channel correlation occurring in the propagation channel. Some analyzed of closed forms are utilized to discuss the phenomenon of channel correlation that exists in MIMO-femtocell systems. Specifically, many numerical results, which are applied to validate the performance of being derived throughput, and the curves match well with the simulation results obtained from the software package. It is noteworthy to remember that if the channel correlation phenomenon is neglected in the performance evaluation of a MIMO-femtocell system over the Rayleigh statistical model, there will be one to about four folds degradation existing in the BS coverage area. Moreover, the number of beam-subset is the other parameter dominates the system performance of a MIMO-femtocell system when the beamforming signaling is applied in the operation.

Honoring the balance of independence versus safety for persons with dementia: Using wearable tech to address wandering behavior

As our population ages a growing number of people will contract dementia. The immense social and economic pressure of this reality creates an urgency to make effective use of wearable technologies that can address wandering behavior associated with dementia to find missing persons and keep them safe. Research has shown that staying physically active and socially engaged is essential in dealing with dementia for those experiencing the disease, their caregivers and families. Wearable technology can assist in striking that fragile balance between supporting the independence of the person with dementia while empowering caregivers and families to keep them safe. It provides peace of mind for caregivers and families knowing wearable technology can be used to track an individual using professional grade multi mode tracking capability. The CareRing created by Insight Care Technologies ticks the boxes of persons with dementia, their caregivers and families by incorporating GPS, cellular triangulation, VHF radio frequency directional finding and safe zone perimeters as well as an on-board accelerometer to detect falls and the ability to sense extremes in temperature either hot or cold into one system. This complete personal safety solution includes a discreet recognizable watch style bracelet with a home base station, internet and cellular interface. It is waterproof, impact resistant with a locking band to ensure it is always in place when needed. Carers are able to establish secure areas and are notified via by text/email alerts should the person with dementia exit a safe zone, fall or be exposed to severe shifts in temperature. All of these features empower caregivers and families to provide security for their loved one while encouraging the independence of those with dementia. If we are to successfully manage the scope of dementia in our future we will need to make use of wearable tech. The ability to harness and integrate today's most progressive technologies to balance independence and safety benefits those with dementia, their caregivers and families. These modern tools will be essential in coping with the social and economic challenges to come.

Adaptive NLOS Mitigation Location Algorithm in Wireless Cellular Network

In a cellular network, a location scenario is considered in this paper, which the home base station (BS) measures the range and angle while neighboring BSs measure the ranges. Based on the range and angle measurements, two adaptive non-line-of-sight (NLOS) identification and mitigation location algorithms with low complexity are proposed. The main idea of our proposed algorithms is to search the optimal subset of range and angle measurements by utilizing the hybrid lines of position algorithm and comparing the normalized residual error to perform the NLOS identification and location. Compared with the existing algorithms, the proposed algorithms have three advantages: one is different to the existing algorithms that require at least three BSs, the proposed algorithms can be suitable for two BSs scenario. Second is the low complexity of our proposed algorithms compared with the existing algorithms. The last is simulation results show that the proposed algorithms outperform the existing algorithms in bad urban and urban environments.

User-Centric Intercell Interference Nulling for Downlink Small Cell Networks

Small cell networks are regarded as a promising candidate to meet the exponential growth of mobile data traffic in cellular networks. With a dense deployment of access points, spatial reuse will be improved, and uniform coverage can be provided. However, such performance gains cannot be achieved without effective intercell interference management. In this paper, a novel interference coordination strategy, called user-centric intercell interference nulling, is proposed for small cell networks. A main merit of the proposed strategy is its ability to effectively identify and mitigate the dominant interference for each user. Different from existing works, each user selects the coordinating base stations (BSs) based on the relative distance between the home BS and the interfering BSs, called the interference nulling (IN) range, and thus interference nulling adapts to each user's own interference situation. By adopting a random spatial network model, we derive an approximate expression of the successful transmission probability to the typical user, which is then used to determine the optimal IN range. Simulation results shall confirm the tightness of the approximation, and demonstrate significant performance gains (about 35-40%) of the proposed coordination strategy, compared with the non-coordination case. Moreover, it is shown that the proposed strategy outperforms other interference nulling methods. Finally, the effect of imperfect channel state information (CSI) is investigated, where CSI is assumed to be obtained via limited feedback. It is shown that the proposed coordination strategy still provides significant performance gains even with a moderate number of feedback bits.

Orthogonal circular polarized transmission for interference control in femto–macro networks

Multi-tier networks comprising of macro-cellular network overlaid with less power, short range, home-base station like femtocells provide an economically feasible solution for meeting the unrelenting traffic demands. However, femtocells that use co-channel allocation with macrocells result in cross-tier interference which eventually degrades the system performance. It is for this reason that, cross-polarized data transmission is proposed in this paper as a potential approach towards improving the spectral efficiency of cellular systems and at the same time permitting co-channel allocation. Here two independent information channels occupying the same frequency band can be transmitted over a single link. The paper evaluates a scenario where femtocell network makes use of right hand circular polarization (RHCP) and macrocell network makes use of left hand circular polarization (LHCP) for signal transmission. The polarizations being orthogonal to each other due to their sense of rotation ensure isolation between the networks and enable both of them to use the same spectral resources simultaneously. Analytical and simulation results prove that this opens the scope for an easily implementable, remarkable opportunity in the context of two-tier femto–macro network that can increase the system capacity. The paper closes by discussing the technical challenges involved in the implementation as well as the possible solutions to overcome the same.

Femtocell Interference, SINR and the Probability of Connection at Downlink

A Femtocell (FMC) is a low power cellular home base station, which is low in cost and operating in licensed spectrum. Nowadays, because of the requirement for high data rate and large area coverage indoors, FMC provides the solution to these requirements. FMC is deployed mainly indoors and sometimes outdoors at the cell edge to increase the area of coverage, capacity and in order to enhance the received signal in the user's premises. In this paper, a novel technique and a Monte Carlo simulation is implemented to calculate the interference, the SINR and the probability of connection at the downlink for a varied number of FMCs based on LTE and WiMAX OFDMA range. Moreover, a novel Monte Carlo simulation is used to carry out the comparison of interference, SINR and probability of connection for three different numbers of FMCs. Furthermore, a novel comparison of FMCs at various SINR threshold values is presented. The downlink interference occurs from neighbouring FMCs to the target user equipment (UE) when the signal transmits from the serving FMC to the target UE and the signals which are transmitted from the neighbouring FMCs would have the same subchannels during the downlink transmission. This paper will explore the appropriate number of FMCs that could serve a specific indoor area and the proper number of UEs in the specified area.