Muhammad Usman Sheikh

ADVANCED ANTENNA TECHNIQUES AND HIGH ORDER SECTORIZATION WITH NOVEL NETWORK TESSELLATION FOR ENHANCING MACRO CELL CAPACITY IN DC-HSDPA NETWORK

Mobile operators commonly use macro cells with traditional wide beam antennas for wider coverage in the cell, but future capacity demands cannot be achieved by using them only. It is required to achieve maximum practical capacity from macro cells by employing higher order sectorization and by utilizing all possible antenna solutions including smart antennas. This paper presents enhanced tessellation for 6-sector sites and proposes novel layout for 12-sector sites. The main target of this paper is to compare the performance of conventional wide beam antenna, switched beam smart antenna, adaptive beam antenna and different network layouts in terms of offering better received signal quality and user throughput. Splitting macro cell into smaller micro or pico cells can improve the capacity of network, but this paper highlights the importance of higher order sectorization and advance antenna techniques to attain high Signal to Interference plus Noise Ratio (SINR), along with improved network capacity. Monte Carlo simulations at system level were done for Dual Cell High Speed Downlink Packet Access (DC-HSDPA) technology with multiple (five) users per Transmission Time Interval (TTI) at different Intersite Distance (ISD). The obtained results validate and estimate the gain of using smart antennas and higher order sectorization with proposed network layout.

Performance evaluation of Adaptive MIMO Switching in Long Term Evolution

In a race towards 4G technologies, future cellular network like Long Term Evolution (LTE) is competing with high data rates and improved spectrum efficiency. The target of this paper is to evaluate performance of Adaptive MIMO Switching (AMS) in LTE in terms of cell throughput and throughput gain with respect to other antenna configuration. The impact of different intersite distance on the performance of AMS was also investigated in this paper. The assessment was based on simulations using analytical channel model. Kronecker channel model without any Channel State Information (CSI) at transmitter was used for the simulation purposes. Adaptive MIMO switching works on the principle of switching among transmit diversity, receive diversity, and spatial multiplexing in accordance to SINR level. Simulation results reveal that significant improvement in cell throughput can be achieved by applying AMS technique. However, utilization of standard MIMO transmission techniques also improves channel capacity.

Evaluation of SPMA and higher order sectorization for homogeneous SIR through macro sites

This paper highlights the performance of single path multiple access (SPMA) and discusses the performance comparison between higher order sectorization and SPMA in a macrocellular environment. The target of this paper is to emphasize the gains and significance of the novel concept of SPMA in achieving better and homogeneous SIR and enhanced system capacity in a macrocellular environment. This paper also explains the algorithm of SIR computation in SPMA. The results presented in this paper are based on sophisticated 3D ray tracing simulations performed with real world 3D building data and site locations from Seoul, South Korea. Macrocellular environment dominated with indoor users was considered for the research purpose of this paper. It is found that by increasing the order of sectorization, SIR along with spectral efficiency degrades due to the increase in inter-cell interference. However, as a result of better area spectral efficiency due to increased number of sectors (cells), the higher order sectorization offers more system capacity compared to the traditional 3-sector site. Furthermore, SPMA shows an outstanding performance and significantly improves the SIR for the individual user over the whole coverage area, and also remarkably increases the system capacity. In the environment under consideration, the simulation results reveal that SPMA can offer approximately 424 times more system capacity compared to the reference case of 3-sector site.

UMTS900 deployment with different call handling strategies

The target of this paper is to investigate different traffic handling strategies to increase the capacity of the network. Impact of deploying UMTS900 with other GSM900/1800 and UMTS2100 layer was also observed in terms of capacity of the network. Number of mobile users is increasing enormously, and it is expected that the demand for data services and different kind of multimedia services will grow with accelerated pace. UMTS2100 has been deployed to meet the requirement of data services. But due to higher frequency band of operation, signals at higher frequencies experience more path loss. Therefore, to provide better coverage to indoor data users more sites of UMTS2100 are required. UMTS900 deployment provides the solution for high deployment cost, and it provides the better coverage as compared to UMTS2100. The deployment of UMTS900 as an overlay with UMTS2100 also helps in enhancing the network capacity, both for the voice traffic and data traffic. A position and service based call handling scheme is proposed in this paper. Results of this paper show that by adopting proposed traffic handling strategy, capacity of the network can be increased.

Impact of penalty time on multilayer network along with UMTS900 deployed with smart traffic handling scheme

The target of this paper is to analyze the impact of penalty time in second generation system in terms of capacity. GSM uses time slots (channels) for carrying traffic, therefore impact of penalty time was only observed in GSM system not in UMTS system. Impact of smart traffic handling scheme was also observed in terms of blocking probabilities. Due to better signal propagation condition at 900 MHz band, it is of keen interest to deploy UMTS900 with other GSM900/1800 and UMTS2100 layer. Handovers are needed to support multilayer and multimode networks e.g. using UMTS and GSM networks together. In this paper, change in overhead traffic caused by additional UMTS900 layer was also analyzed. Extensive number of handovers causes loss in network traffic handling capacity. A compact and organized smart traffic handling is given in this paper which is based on the location of the user, distance of the user from the base station and required service type. The concept of overlay - underlay configuration was also exploited in smart traffic handling scheme.

SPMA: An innovative solution for future smart networks in macrocellular suburban environment

To cope with the gigantic capacity demand of future networks, the research towards the Fifth Generation (5G) of mobile networks is currently ongoing in full swing. In the first part of this paper, it focuses on the possible gains of selecting an optimum antenna downtilting, suitable antenna beamwidth and highlights the gain of using higher order sectorization in optimizing the network capacity of traditional cellular networks. It highlights the limitations of available solutions in meeting the target of 1000 times more capacity with reference to the 4G network. In the second part of the paper, an innovative concept of Single Path Multiple Access (SPMA) for macrocellular environment is discussed, which can significantly improve the system capacity by aggressively reusing the available spectrum. The essence of SPMA is to avoid interference and reuse the frequency spectrum by employing narrow needle beams. Comprehensive 3D ray tracing simulations were done using real world building and site data to compare the performance of traditional solutions and SPMA. The obtained results indicate that antenna downtilting, optimum beamwidth and higher order sectorization enhances the system capacity, but with only small margin. However, the revolutionary concept of SPMA improved the system capacity by substantial margin.

SPMA: A Centralized Macrocellular Approach for Enhancing System Capacity of Future Smart Networks

To cope with the gigantic capacity demand of future networks, the research towards the Fifth Generation (5G) of mobile networks is currently ongoing in full swing. In the first part of this paper, it focuses on the possible gains of selecting an optimum antenna downtilting, suitable antenna beamwidth and highlights the gain of using higher order sectorization in optimizing the network capacity of traditional cellular networks. It highlights the limitations of available solutions in meeting the target of 1000 times more capacity with reference to the 4G network. In the second part of the paper, an innovative concept of Single Path Multiple Access (SPMA) for macrocellular environment is discussed, which can significantly improve the system capacity by aggressively reusing the available spectrum. The essence of SPMA is to avoid interference and reuse the frequency spectrum by employing narrow needle beams. Comprehensive 3D ray tracing simulations were done using real world building and site data to compare the performance of traditional solutions and SPMA. The obtained results indicate that antenna downtilting, optimum beamwidth and higher order sectorization enhances the system capacity, but with only small margin. However, the revolutionary concept of SPMA improved the system capacity by substantial margin.

Analysis of Outdoor and Indoor Propagation at 15 GHz and Millimeter Wave Frequencies in Microcellular Environment

A R T I C L E I N F O A B S T R A C T Article history: Received: 26 November, 2017 Accepted: 07 January, 2018 Online: 30 January, 2018 The main target of this article is to perform the multidimensional analysis of multipath propagation in an indoor and outdoor environment at higher frequencies i.e. 15 GHz, 28 GHz and 60 GHz, using “sAGA” a 3D ray tracing tool. A real world outdoor Line of Sight (LOS) microcellular environment from the Yokusuka city of Japan is considered for the analysis. The simulation data acquired from the 3D ray tracing tool includes the received signal strength, power angular spectrum and the power delay profile. The different propagation mechanisms were closely analyzed. The simulation results show the difference of propagation in indoor and outdoor environment at higher frequencies and draw a special attention on the impact of diffuse scattering at 28 GHz and 60 GHz. In a simple outdoor microcellular environment with a valid LOS link between the transmitter and a receiver, the mean received signal at 28 GHz and 60 GHz was found around 5.7 dB and 13 dB inferior in comparison with signal level at 15 GHz. Whereas the difference in received signal levels at higher frequencies were further extended in an indoor environment due to higher building penetration loss. However, the propagation and penetration loss at higher frequency can be compensated by using the antenna with narrow beamwidth and larger gain.

Enhanced Outdoor to Indoor Propagation Models and Impact of Different Ray Tracing Approaches at Higher Frequencies

A R T I C L E I N F O A B S T R A C T Article history: Received: 26 November, 2017 Accepted: 05 February, 2018 Online: 08 March, 2018 The main target of this article is to study the provision of indoor service (coverage) using outdoor base station at higher frequencies i.e. 10 GHz, 30 GHz and 60 GHz. In an outdoor to indoor propagation, an angular wall loss model is used in the General Building Penetration (GBP) model for estimating the additional loss at the intercept point of the building exterior wall. A novel angular wall loss model based on a separate incidence angle in azimuth and elevation plane is proposed in this paper. In the second part of this study, an Extended Building Penetration (EBP) model is proposed, and the performance of EBP model is compared with the GBP model. In EBP model, the additional fifth path known as the “Direct path” is proposed to be included in the GBP model. Based on the evaluation results, the impact of the direct path is found significant for the indoor users having the same or closed by height as that of the height of the transmitter. For the indoor users located far away from the exterior wall of building, a modified and enhanced approach of ray tracing type is proposed in this article. In the light of acquired simulation results, the impact of a modified ray tracing approach is emphasized.

Angular wall loss model and Extended Building Penetration model for outdoor to indoor propagation

The main target of this research work is to study the provision of indoor service (coverage) using outdoor base stations at higher frequencies i.e. 10 GHz in the context of a single building scenario. In an outdoor to indoor propagation, an angular wall loss model is used in the General Building Penetration (GBP) model for estimating the additional loss at the intercept point of the building exterior wall. A novel angular wall loss model based on a separate incidence angle in azimuth and elevation plane is proposed in this paper. In the second part of this study, an Extended Building Penetration (EBP) model is proposed, and the performance of EBP model is compared with the GBP model. In EBP model, the additional fifth path known as the “Direct path” is proposed to be included in the GBP model. Based on the evaluation results, the impact of the direct path is found significant for the indoor users having the same or closed by height as that of the height of the transmitter.