Point-to-multipoint Research Articles

Development of Long-Range and High-Speed Wireless LAN

The development of long-range and high-speed wireless LAN (Local Area Network) technologies has become increasingly important in modern networking applications. We have developed 2.4 GHz wireless LAN units with the longest coverage, which comply with the IEEE 802.11g standard and Indian radio regulations, to re-establish communications temporarily between disaster-devastated areas and hospitals, among other locations. The network deployment is carried out in the college campus, involving two types: a) point-to-point (PtP), and b) point-to-multipoint (PtMP). The throughput within ranges of 500m and 6Km is approximately 100 Mbps, while for 15Km, the achieved throughput was 80 Mbps. Real-world applications and use cases of long-range wireless LAN systems are also highlighted to demonstrate their significance in diverse scenarios, ranging from rural connectivity to urban deployments

What is beyond 50G: future standards of optical access networks [Invited

In the past two decades, optical access networks have been widely deployed by operators around the world. The global optical access network market reaches about 1 billion users with a revenue of over 10 billion US dollars. As strategic tools to facilitate mass production, the optical access network standards play a crucial role in driving the product deployment and market growth. This paper overviews the latest effort in international standards bodies on the next generation optical access networks. It discusses projects in this area within the International Telecommunication Union’s Telecommunication Standardization Section (ITU-T), the IEEE, and the European Telecommunications Standards Institute (ETSI). Promising technologies are investigated with the goal of providing rates beyond 50 Gbps. Challenges are highlighted to satisfy the requirements on balancing access rates, loss budgets, and cost. Candidate systems are analyzed in three categories: point-to-multipoint (PtMP), point-to-point (PtP), and new applications. These standardization endeavors will jointly guarantee optical access networks as the premiere solution of wireline broadband access.

Spatial Nonlinear Conversion of Structured Light for Machine Learning Based Ultra‐Accurate Information Networks

AbstractStructured light can be encoded to carry information for free‐space optical communications with an extended degree of freedom to increase the capacity, however, the accuracy issue along with capacity increase is one of the biggest challenges that prevent practical applications. To achieve high accuracy with high capacity by a simple method, they propose the spatial nonlinear conversion of structured light into a communication network, especially, realizing an ultra‐high‐accuracy point‐to‐multipoint (PtoMP) information transmission link. A series of coherently superposed spatial modes and their spatial nonlinear conversion states are used as information carriers to replace the prior orbital angular momentum beams and greatly expand channel capacity within quite low spatial mode order. Through the spatial nonlinear conversion of simple dual‐mode superposition and a very basic neural network for machine learning‐based recognition, as high as 99.5% accuracy for more than 500 modes is obtained. By a combination of diffuse reflection screens and multiple CCDs, the large observation angle PtoMP information transmission is also proved to be feasible. This work paves the way for practical large‐scale multi‐party information networks using structured light.

A 51 Gb/s Reconfigurable mmWave Fiber-Wireless C-RAN Supporting 5G/6G MNO Network Sharing

The growing demand for ubiquitous broadband connectivity in 5G/6G Radio Access Networks (RANs) has turned Centralized RAN (C-RAN) and reconfigurable Point-to-MultiPoint (PtMP) network topologies into the mainstream approach for keeping pace with the vastly increasing traffic capacities and connection densities. Relying on an all-passive Arrayed Waveguide Grating Router (AWGR), we propose and demonstrate reconfigurable allocation of multiple parallel Fiber-Wireless (FiWi) millimeter wave (mmWave) analog (Intermediate Frequency over Fiber) IFoF interfaces. The proposed technology provides a framework for the implementation of reconfigurable multiple FiWi backhaul /midhaul/fronthaul (X-haul) connections. The use of AWGR enables wavelength slicing and the co-existence of multiple transport links over the same X-haul network infrastructure. The proposed concept is experimentally validated by two sets of experimental measurements. More specifically a 4λ- Wavelength-Division Multiplexed (WDM) signals modulated by IFoF signals are routed through the AWGR and wirelessly transmitted over the air across a 1m V-band distance by two different pairs of mmWave 60 GHz antennas. In the first experiment, a Phased Array Antenna (PAA) operating at 60 GHz is utilized achieving a 2.5 Gb/s data rate per wavelength and beam pair with an Error Vector Magnitude (EVM) of less than 12.5% and an aggregate 10 Gb/s traffic capacity. The achieved performance meets for the first time the respective 5G Key Performance Indicator (KPI) requirements for EVM quality and peak data traffic while supporting the link reconfiguration wavelength routing and mmWave beam direction. In the second experiment, the PAA is replaced by a point-to-point 60 GHz link utilizing a high-end mm-wave transmitter, thus achieving a data rate of 12.75 Gb/s per wavelength-beam with an EVM of less than 6.5% and an aggregate capacity of 51 Gb/s. To this end, the proposed solution is shown to form a promising roadmap toward flexible and reconfigurable 5G/6G mmWave C-RAN architectures where multiple Mobile Network Operators (MNOs) can share the same network infrastructure and dynamically allocate fiber, antenna beams and wavelengths.

Hardware-Efficient, Ultra-Fast and Joint Polarization and Carrier Phase Tracking Scheme Based on Frequency Domain Pilot Tones for DSCM Systems

The coherent digital subcarrier multiplexing (DSCM) has recently been proposed as a cost saving solution to realize flexible and scalable point-to-multipoint (PTMP) networks. In this work, a hardware-efficient, ultra-fast and joint polarization and carrier phase tracking scheme for the DSCM systems based on frequency domain pilot tones (named as PTJ) is proposed and demonstrated via both simulations and experiments. By extracting the amplitude and phase of the pilot tones with a low-pass filter (LPF), the transmission matrix of random birefringence and carrier phase can be obtained prior to subcarrier demultiplexing and channel equalization. For the hardware-efficient implementation, a simplified LPF based on sliding window averaging (SWA) is proposed to filter out the pilot tones. Compared to previous scheme using pilot tones to track polarization and carrier phase in a cascaded manner (named as PTC), our proposed scheme shows better BER performance over wide polarization rotation rates and reduces more than 90% of computation resources by the SWA and joint tracking of polarization and carrier phase. The experimental results show that the proposed scheme can track polarization rotation rate up to 20 Mrad/s with the OSNR penalty of 0.2 dB at 7% FEC threshold. This indicates that an OSNR sensitivity gain of 2.8 dB is achieved compared with the PTC scheme. The proposed scheme provides a hardware-efficient and fast-tracking solution to recovery the polarization and carrier phase for digital subcarrier multiplexing (DSCM) and polarization division multiplexing (PDM) based optical fiber communication system.

Real-Time DSP-Free 100 Gbit/s/λ PAM-4 Fiber Access Link Using EML and Direct Detection

A 100 Gbit/s/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> PAM-4 fiber link with an optical budget of 30 dB and 20 km fiber reach is achieved in real time experiments. This is compliant with class A (20 dB) point to point (PtP) applications as mobile fronthaul for example, and with class N1 (29 dB) point to multipoint (PtMP) for residential market. We used an integrated externally modulated laser, an analog pre-equalizer, an optical booster amplifier and/or non-filtered preamplifier and direct detection without any digital signal processing (whether real-time or offline).

Asymmetric point-to-multipoint coherent architecture with a frequency aliasing recovery algorithm for cost-constraint short-reach access networks.

An asymmetric point-to-multipoint (PTMP) coherent architecture combined with a frequency aliasing recovery (FAR) algorithm is proposed for cost-constraint short-reach access networks. In this architecture, the uplink transmitters are simplified significantly with the uplink dual-polarization four-level pulse amplitude modulation (DP-PAM4) and downlink DP quadrature phase shift keying (DP-QPSK) asymmetric transmission design. Digital to analog converters (DACs) and radio frequency (RF) drivers are reduced by half, and in-phase and quadrature modulators (IQMs) are replaced by Mach-Zehnder modulators (MZMs), saving four MZ interferometers (MZIs). Furthermore, based on the asymmetric architecture, the FAR algorithm can recover signals from frequency aliasing caused by frequency offset (FO), even when half of the signal spectrum is aliased. This algorithm enables the asymmetric architecture to narrow down guard bands between subcarriers or even overlap the subcarriers, saving the receiver bandwidth at the aggregation/hub side. The performance of the asymmetric uplink DP-PAM4 transmission with the FAR algorithm is evaluated in both simualations and experiments. The effects of laser linewidths and IQ skew on the performance of the FAR algorithm are also analyzed. Simulation results show the algorithm can recover 16 Gbaud and 32 Gbaud signal from 8 GHz and 16 GHz aliasing, respectively. In the experiments with 10 km fiber transmissions, the FAR algorithm can recover 10 Gbaud signals from 5 GHz frequency aliasing, saving about 20.83% of the total receiver bandwidth in a 2-subcarrier system.

A MmWave communication testbed based on IEEE 802.11ad with scalable PtMP configuration

The sub-6G band is too crowded to accommodate higher data rate, while the millimeter wave (mmWave) bands have abundant spectrum resources and massive MIMO can provide high spectral and energy efficiency. Therefore, the combination of the two, namely mmWave-MIMO system, has attracted intensive research interests. In this paper, we develop a high-speed mmWave-MIMO communication system and conduct exhaustive field tests. The detail of the system design is provided and the key modules of the testbed are analyzed. The testbed exploits high gain of mmWave RF and flexible configuration of embedded system. The validation and field tests show that the developed testbed can provide up to 2.3 Gbps network layer data rate in single channel with low latency and support point-to-multi-point (PtMP) transmission aided by relay. The testbed can be used in future B5G and 6G systems to provide high reliability and low latency wireless coverage.

A Point-to-Multi-Point Tracking System for FSO Communication

Free space optics (FSO) is considered primarily for establishing point-to-point (PtP). However, due to the increasing demand for mobile platforms and mechanisms to establish point-to-multipoint (PtM) connections, this research proposes and implements a novel PtM tracking mechanism for FSO communication. The alignment mechanism consists of two tracking systems, i.e., coarse tracking and fine-tuning. The coarse tracking is responsible to locate FSO transceivers placed at different positions by using magnetometer sensors connected to the cloud. On the other hand, the fine-tuning mechanism overcomes high-frequency amplitude oscillation or jitter with a displacement range of 8 cm. The link is continuously monitored and if the link is lost or not established after a pre-determined time, then the reference line-of-sight (LoS) angle is updated in the cloud to provide an alternate connection. The stability of the closed-loop system is analyzed in terms of root locus and step response. The proposed PtM system is experimentally validated with FSO terminals located at different locations and distances over indoor and outdoor environments. The proposed method achieved an alignment time of less than 5 s for ten degrees of misalignment.

RIoT: A Routing Protocol for the Internet of Things†

AbstractThe routing protocol for low-power and lossy networks (RPL) is a standard routing framework for Internet of Things (IoT). It supports multipoint-to-point (MP-to-P), point-to-point (P-to-P) and point-to-multipoint (P-to-MP) communications. It is known that RPL’s control overhead can result in the protocol’s poor performance in P-to-P and P-to-MP communications especially in its non-storing mode of operation. Here, we present a routing protocol for the Internet of Things (RIoT) that supports MP-to-P, P-to-P and P-to-MP communications. The protocol can construct P-to-P and P-to-MP routes with relatively lower control overhead. Another salient feature of RIoT is that it supports multiple gateways in the same network with an aim to reduce memory requirement for storing a forwarding table. Furthermore, RIoT is also capable of handling mobility-based IoT use cases. To facilitate communication among nodes connected to different gateways in the same network, here we also present an inter-gateway communication mechanism. We implemented RIoT in the Contiki operating system, and it is extensively evaluated using emulation and real testbed-based experiments. We analyzed the impact of the number of gateways, radio duty cycling (RDC) and mobility on the routing protocols’ performance. Our results demonstrate that either with or without RDC RIoT demonstrates statistically significantly better packet delivery ratio, per-packet end-to-end delay and control overhead compared to the RPL-based protocol. RIoT’s multi-gateway communication architecture substantially reduces the memory requirement to store a forwarding table. Our results also demonstrate that multiple gateways in a network reduce the network partitioning problem in mobile scenarios. Hence, RIoT also demonstrates better performance in mobile scenarios compared to the RPL-based protocol.

PERFORMANCE IMPROVEMENT OF THE BASE STATION ANTENNA BY USING MIMO IN MOBILE COMMUNICATION SYSTEM

This paper presents a design of base station antenna with high performance dual-polarized network sites and 4X4 MIMO Sector Antenna subscriber sites with sturdy constructions for micro-base-station applications. In this research the proposed one is design dual-polarized network sites are 5.25-5.85 GHZ, 2-FT (0.6M) height for point to point (PTP) link and point to multi point (PMP) link ePMP 4x4 MU-MIMO Sector Antenna for subscriber module at ePMP 3000, 5.8 GHz (5825 to 5875 MHz) Access Point RF frequency band for SU-MIMO 4X4 MIMO mode of transmission. Those frequencies used is the fifth generation (5G) mobile network planning and it improves the performance of the network in terms of coverage and capacity by using 4X4 MIMO antennas for indoor propagation model. Measured that the results shows the antenna has a 45MHz RF channel bandwidth with Antenna Gain is 28.58 dBi, port Free Space Path Loss is more than 117.53 dB and Performance 99.9995 % for 10.0 Mbps. This can be utilized for broadband base station in the cutting edge wireless correspondence framework. The Link Planner has been used to simulate network coverage and throughput performance of 4X4 MIMO antenna configurations of the deployed networks. The average simulated throughput per sector of 4X4 MIMO configuration was seen to be better than the 2X2 MIMO configuration.

5G Radio Access Networks: Enabling Efficient Point-to-Multipoint Transmissions

The launch of 5G technology based on 3rd Generation Project Partnership (3GPP) Release 15 was completed in December 2018. An open issue with this release of standards is that it supports only unicast communications in the core network and point-to-point (PTP) transmissions in the radio access network (RAN) but does not support multicast/broadcast communications and point-to-multipoint (PTM) transmissions, which are 3GPP system requirements for 5G applications in a number of vertical sectors, including automotive, airborne communications, Internet of Things (IoT), media and entertainment, and public warning and safety systems. In this article, we present novel mechanisms for enhancing the 5G unicast architecture with a minimal footprint so as to enable efficient PTM transmissions in the RAN and support multicast communications in the Release 15 core as a built-in delivery optimization feature of the system. This approach will enable completely new levels of network management and delivery cost efficiency.

Physical Layer Performance Evaluation of LTE-Advanced Pro Broadcast and ATSC 3.0 Systems

This paper provides a detailed performance analysis of the physical layer of two state-of-the-art point-to-multipoint (PTM) technologies: evolved Multimedia Broadcast Multicast Service (eMBMS) and Advanced Television Systems Committee - Third Generation (ATSC 3.0). The performance of these technologies is evaluated and compared using link-level simulations, considering relevant identified scenarios. A selection of Key Performance Indicators for the International Mobile Telecommunications 2020 (IMT-2020) evaluation process has been considered. Representative use cases are also aligned to the test environments as defined in the IMT-2020 evaluation guidelines. It is observed that ATSC 3.0 outperforms both eMBMS solutions, i.e., MBMS over Single Frequency Networks (MBSFN) and Single-Cell PTM (SC-PTM) in terms of spectral efficiency, peak data rate and mobility, among others. This performance evaluation serves as a benchmark for comparison with a potential 5G PTM solution.

Earning Maximization With Quality of Charging Service Guarantee for IoT Devices

Resonant beam charging (RBC) is a promising wireless power transfer technology to provide long-range, high-power, mobile, and safe wireless power for the Internet of Things devices. The point-to-multipoint (PtMP) RBC system can charge multiple receivers simultaneously similar to WiFi communications. To guarantee the quality of charging service (QoCS) for each receiver and maximize the overall earning in the PtMP RBC service, we specify the charging pricing strategy and develop the high priority charge (HPC) scheduling algorithm to control the charging order and power allocation. Each receiver is assigned a priority, which is updated dynamically based on its state of charging (SOC) and specified charging power. The receivers with high priorities are scheduled to be charged in each time slot. We present the pseudo code of the HPC algorithm based on quantifying the receiver's SOC, discharging energy, and various relevant parameters. Relying on simulation analysis, we demonstrate that the HPC algorithm can achieve better QoCS and earning than the round-robin charge scheduling algorithm. Based on the performance evaluation, we illustrate that the methods to improve the PtMP RBC service are: 1) limiting the receiver number within a reasonable range and 2) prolonging the charging duration as long as possible. In summary, the HPC scheduling algorithm provides a practical strategy to maximize the earning of the PtMP RBC service with each receiver's QoCS guarantee.

Point-to-multipoint and ring network communication based on chaotic semiconductor lasers with optical feedback.

In this paper, two configurations of point-to-multipoint (PTM) and ring networks, based on the chaotic semiconductor laser subject to optical feedback, are investigated. A bifurcation diagram and the maximum Lyapunov exponent in the system have been used to distinguish the existence of chaos, and the complex degree of chaotic output is measured through Lempel-Ziv complexity. These results show that feedback strength has a significant effect on the dynamics of the system, namely, an increase in it can induce the system to enter into chaos. In the PTM model, it can be seen that the arbitrary receiver laser (RL) and central transmitter laser (TL) are identically synchronized, and moreover, the synchronization solutions are robust; the message can be encoded by modulating the bias current of the central TL, and at each RL end, the message from TL can be simultaneously recovered by monitoring the power error between RL and TL. As a result, the unidirectional broadcast message transmission, based on PTM, can be well achieved. In the ring network configuration, the coupling between two adjacent lasers through a partially transparent mirror induces the delay and chaotic dynamics. We prove that the dynamics is identically synchronized, and the synchronization against external perturbation also possesses good robustness; the messages introduced on the two arbitrary lasers in this ring network can be simultaneously exchanged.

Data Path Management Mechanism to Mesh Base Stations in WiMAX

Three options are popular today for design of wireless networks - Point-to-Point, Point-to-Multipoint and Mesh topologies. Worldwide interoperability of microwave access (WiMAX) is most often associated with the point-to-multipoint (PMP) topology. For some requirements, the configuration of the base stations (BSs) is aimed to be as mesh. Mesh offers a combination of point-to-point and point-to-multipoint capability by having each of the base station able to communicate with other base stations. This averts the base station element in the standard, besides the process flow across relevant interfaces. The paper proposes a Distributed Data Path Function (DDPF) that allows peers/network elements to exchange data traffic between meshed base stations where WiMAX doesn't allow this. The proposed solution is layer-3 and includes the design of a routing table for a mesh configuration of cell-site (radio base station) routers with a base station controller. Some changes are needed which will be explored throughout the paper promoted with figures to illustrate the idea.

Point-to-Multipoint Communication Enablers for the Fifth Generation of Wireless Systems

3GPP has enhanced the point-to-multipoint (PTM) communication capabilities of 4G LTE in all releases since the adoption of eMBMS in Release-9. Recent enhancements cover not only television services, but also critical machine-type and vehicular communications, following the backward-compatibility design philosophy of LTE. This article discusses the opportunity in the design and standardization of 5G to break with the existing paradigm for PTM transmissions in 4G LTE, where broadcast PTM transmissions were initially conceived as an add-on and pre-positioned service. 5G brings the opportunity to incorporate PTM capabilities as built-in delivery features from the outset, integrating point-to-point and PTM modes under one common framework and enabling dynamic use of PTM to maximize network and spectrum efficiency. This approach will open the door to completely new levels of network management and delivery cost efficiency. The article also discusses the implications of PTM for network slicing to customize and optimize network resources on a common 5G infrastructure to accommodate different use cases and services taking into account user density.

Reliability of Broadcast Communications Under Sparse Random Linear Network Coding

Ultra-reliable Point-to-Multipoint (PtM) communications are expected to become pivotal in networks offering future dependable services for smart cities. In this regard, sparse Random Linear Network Coding (RLNC) techniques have been widely employed to provide an efficient way to improve the reliability of broadcast and multicast data streams. This paper addresses the pressing concern of providing a tight approximation to the probability of a user recovering a data stream protected by this kind of coding technique. In particular, by exploiting the Stein--Chen method, we provide a novel and general performance framework applicable to any combination of system and service parameters, such as finite field sizes, lengths of the data stream and level of sparsity. The deviation of the proposed approximation from Monte Carlo simulations is negligible, improving significantly on the state of the art performance bounds.

Entropy Analysis of Broadband Wireless Access Systems

A Broadband Wireless Access (BWA) system consists of a base station and a set of $M$ users within its antenna sector, with $N$ simultaneously active users, $0\le N\le M$ , working in Point-to-Multipoint (PMP) mode. We model this system as family of Birth–Death Processes (BDPs), with size $M+1$ , in equilibrium, indexed by system utilization parameter $\rho$ , ratio of its primary birth and death rates. Relying on the fundamental concepts of system information $i$ and system entropy $S=E(i)$ , we develop an entropy analysis of BWA systems. Thereby, by definition, the system entropy, as the mean value of system information, is the uncertainty, related to the system. Taking system information as loss function, we identify risk and uncertainty, related to the system. Using the maximization of entropy, given the average number $\overline{N}$ of active users, we promote belt-zone of deviation from maximum uncertainty and a function of relative risk, regarding $\overline{N}$ , for a BWA system. This analysis is illustrated on BWA systems with finite user population, such as the binomial $M$ -server BWA systems, modeled by the family of BDPs with binomial distribution, and the delay single-server BWA systems, modeled by the corresponding family of BDPs; both systems represent private networks.

An Uncertainty Quantification methodology for Broadband Wireless Access systems

A Broadband Wireless Access (BWA) system comprises a Base Station and a group of M users in its vicinity, simultaneously serving N active users, N∈{0,1,2,…,M}, in Point-to-Multipoint (PMP) fashion. Depending on the concepts of system information and system entropy (i.e., mean information) we promote an Uncertainty Quantification (UQ) methodology for BWA systems. We evaluate the measures: system entropy (which represents the uncertainty, inherent to any system), average number of simultaneously active users, system resource utilization and availability, and average throughput per user, with respect to the parameters: system utilization and system size. Entropy is studied through its both components: nominal part and additional part. In information linear BWA system the additional part of entropy vanishes. Moreover, this methodology offers an entropy-based procedure for system utilization parameter estimation, showing that Maximum Likelihood Method (as an estimation procedure) and Fisher Information (as an uncertainty measure) can be successfully applied only to the information linear BWA system. Thus, the change of BWA system features is inherently built in this approach through the change of entropy additional part. Further, using the function of relative risk, given the active user average number, we quantitatively show that smallest uncertainty is associated to the Binomial BWA system (representing a private network), greater to the Erlang loss BWA system, and greatest at all to the information linear BWA system (both representing public networks), where the quantity N obeys Binomial, truncated Poisson and truncated geometrical distribution, respectively.