Microcell Networks Research Articles

Secured THz communication in photonic microcell networks based on spatial wave mixing of steered beams

Future 6G communication systems are envisioned to expand their carrier frequency to the THz region, where a broad unexplored region of spectrum is available. With this expansion, THz wireless communication has the potential to achieve ultra-high data transmission rates of up to 100Gbit/s. However, as large amounts of data are transmitted in an open wireless environment, there are significant concerns regarding communication security due to the susceptibility to eavesdropping, interception, and jamming. In this work, we proposed a secure approach for THz wireless communication based on spatial wave mixing and flexible beam steering. To achieve this, two frequency-modulated THz waves, which are generated by photonic THz sources and carry encrypted information with true randomness, are mixed at a THz envelope detector with an exclusive-OR logic operation. We analyzed the possible spatial location for the THz detector to ensure a secure microcell network deployment. Our results demonstrate that the size of the decryptable region is directly dependent on the directivity and width of the emitted THz beam. To address this, we have developed an array antenna with integrated uni-traveling-carrier photodiodes (UTC-PDs), which is capable of generating THz waves while also improving the flexibility of beam pointing, allowing for greater control over the location and size of the decodable region. By controlling fiber-optic delay lines, we successfully demonstrated that the directional gain of a 200GHz wave is increased by 8dB through a 1 × 3 UTC-PD-integrated planar bowtie antenna (PBA) array, together with continuous beam steering from -20° to 10°. Additionally, using a 1 × 4 UTC-PD-integrated PBA array to emulate two encryption transmitters and a Femi-level managed barrier diode to detect spatially mixed THz waves, we successfully achieved a feasibility experiment for real-time 200Mbit/s location-based decryption in the 200GHz band. These results indicate that the proposed scheme is feasible for secured THz communication, and would be a powerful candidate to mitigate security risks in 6G microcell networks.

Online Multicell Coordinated MIMO Wireless Network Virtualization With Imperfect CSI

We consider online coordinated precoding design for downlink wireless network virtualization (WNV) in a multi-cell multiple-input multiple-output (MIMO) network with imperfect channel state information (CSI). In our WNV framework, an infrastructure provider (InP) owns each base station that is shared by several service providers (SPs) oblivious of each other. The SPs design their precoders as virtualization demands for user services, while the InP designs the actual precoding solution to meet the service demands from the SPs. Our aim is to minimize the long-term time-averaged expected precoding deviation over MIMO fading channels, subject to both per-cell long-term and short-term transmit power limits. We propose an online coordinated precoding algorithm for virtualization, which provides a fully distributed semi-closed-form precoding solution at each cell, based only on the current imperfect CSI without any CSI exchange across cells. Taking into account the two-fold impact of imperfect CSI on both the InP and the SPs, we show that our proposed algorithm is within an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$O(\delta)$ </tex-math></inline-formula> gap from the optimum over any time horizon, where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\delta $ </tex-math></inline-formula> is a CSI inaccuracy indicator. Simulation results validate the performance of our proposed algorithm under two commonly used precoding techniques in a typical urban micro-cell network environment.

Range expansion method on heterogeneous network to increase picocell coverage

In this study, picocell planning was carried out on heterogeneous networks by applying the range expansion method. The case study was conducted in Coblong Subdistrict-Bandung on the 1800 MHz frequency. Heterogeneous network (HetNet) is a system that combines microcell networks and small cell networks (picocell and femtocell). The application of the range expansion method in picocell was aimed to broaden the scope of picocell. For the simulation, Atoll 3.3.0 software with observational parameters was implemented, including RSRP, SINR, throughput, and user connected. The planning results showed that the application of expansion method increased the coverage and quality of network, where the RSRP value ≥ -90 dBm was 97.72%, SINR ≥ 5 dB was 70.99%, uplink throughput was 17.80 Mbps, downlink throughput was 21.37 Mbps, and user connected was 99.2%.

Optimal power allocation for multiuser OFDM-based cognitive heterogeneous networks

Heterogeneous network (HetNet) as a promising technology to improve spectrum efficiency and system capacity has been concerned by many scholars, which brings huge challenges for power allocation and interference management in multicell network structures. Although some works have been done for power allocation in heterogeneous femtocell networks, most of them focus centralized schemes for single-cell network under interference constraint of macrocell user. In this paper, a sum-rate maximization based power allocation algorithm is proposed for a downlink cognitive HetNet with one macro-cell network and multiple microcell networks. The original power allocation optimization problem with the consideration of cross-tier interference constraint, maximum transmit power constraint of microcell base station and inter-cell interference of microcell networks is converted into a geometric programming problem which can be solved by Lagrange dual method in a distributed way. Simulation results demonstrate the performance and effectiveness of the proposed algorithm by comparing with the equal power allocation scheme.

Coordinated SLNR Based Precoding in Large-Scale Heterogeneous Networks

This paper focuses on the downlink of large-scale two-tier heterogeneous networks composed of a macrocell overlaid by microcell networks. Our interest is on the design of coordinated beamforming techniques that allow to mitigate the intercell interference. Particularly, we consider the case in which the coordinating base stations have imperfect knowledge of the channel state information. Under this setting, we propose a regularized signal-to-leakage-and-noise ratio (SLNR) based precoding design in which the regularization factor is used to allow better resilience with respect to the channel estimation errors. Based on tools from the random matrix theory, we provide an analytical analysis of the signal-to-noise ratio and SLNR performances. These results are then exploited to propose a proper setting of the regularization factor. Simulation results are finally provided in order to validate our findings and to confirm the performance of the proposed precoding scheme.

SCAN RADIO FREKWENSI (RF) DRIVE TEST DALAM TELEKOMUNIKASI

In order to explore the potential candidates for employment, then in the world of school or college need to conduct scouting systematically between education obtained from any school or college with the business world. This can be realized through practical work so that students will be directed to achieve a professional competence. Planning is to get the optimal use of resources and maximum revenue potential while maintaining the level of quality of the system. In addition to cost considerations and spectrum allocation should also be considered. A system must be well planned so that when traffic increases, the capacity can be increased. Because the environment in each region is different, so different each macrocell and microcell network. Therefore, accurate planning is essential to ensure that the system can be enhanced capacity and improved network quality. RF planning has an important role in the design of mobile. With proper growth plan, we can reduce a lot of the problems that may arise and also reduce the cost optimization. However, if planning is bad then it will appear a lot of problems on the network and also increase the cost optimization. Keyword : Scan Radio, Frekwensi. Telekonumikasi

SCAN RADIO FREKWENSI (RF) DRIVE TEST DALAM TELEKOMUNIKASI

In order to explore the potential candidates for employment, then in the world of school or college need to conduct scouting systematically between education obtained from any school or college with the business world. This can be realized through practical work so that students will be directed to achieve a professional competence. Planning is to get the optimal use of resources and maximum revenue potential while maintaining the level of quality of the system. In addition to cost considerations and spectrum allocation should also be considered. A system must be well planned so that when traffic increases, the capacity can be increased. Because the environment in each region is different, so different each macrocell and microcell network. Therefore, accurate planning is essential to ensure that the system can be enhanced capacity and improved network quality. RF planning has an important role in the design of mobile. With proper growth plan, we can reduce a lot of the problems that may arise and also reduce the cost optimization. However, if planning is bad then it will appear a lot of problems on the network and also increase the cost optimization.

Extract Non-Line-of-Sight state of base stations and error mitigation technique for wireless localization in micro-cell networks

Non Line of Sight (NLOS) propagation is a challenging issue which the performance of network based wireless localization is limited by errors primarily caused by NLOS corruption. NLOS is inherently a dominant source of errors in metropolitan area wireless networks, like cellular one, so in this paper we discuss our proposed algorithm within cellular network terminology. This paper contributes two novel algorithms. The first one is to extract the NLOS state of base station (BS) and the second one is a correction algorithm to enhance the measurements accuracy. Our proposed algorithm discuses a novel localization technique to estimate true mobile terminal (MT) location from a set of possibly high NLOS errors and furthermore it can recognize the NLOS states of BSs. Our algorithm utilizes a constrained approach, when range measurements are available from three BSs. Simulations studying the performance of algorithm and demonstrates that mean location error (MLE) over corresponding MT roaming area is nearly independent of the magnitude of NLOS error and can be smaller than 0.005 of cells diameter even in large NLOS error.