Energy-Efficient Traffic Steering in Millimeter-Wave Dual Connectivity Discontinuous Reception Framework

The first phase of new radio (NR) standard, which was finalized in December 2017, is called a non‐standalone (NSA) NR as it is based on dual connectivity between an LTE radio access technology (RAT) and the NR RAT, known also as E‐UTRA – NR Dual Connectivity(EN‐DC). This chapter presents an overview of 5G core (5GC) network and functionalities by presenting the specified logical network nodes which are the standardized building blocks for the 5GC and by giving an example of a signaling flow between the nodes for connection establishment. It discusses the different dual connectivity options and related terminology. Two different protocol stacks exist in NR system: control plane protocol stack, carrying control information between user equipment (UE) and gNB or Core Network, and user plane protocol stack, carrying data between different applications in the UE and in the network.

The 3rd generation partnership project (3GPP) has recently specified the non-standalone 5G New Radio (NR), in which the dual connectivity (DC) feature plays an essential role. A User Equipment (UE) with DC is able to concurrently connect to an evolved NodeB (eNB) (e.g., using LTE in a macro cell) and a next generation NodeB (gNB) (e.g., using 5G NR in a small cell) aiming to satisfy the 5G's required Key Performance Indicators (KPIs). In this work, we focus on the issue of concurrent transmissions on the 5G small cell, which potentially exploit the benefits of DC. With DC, an application is able to spread its traffic over different two paths (via eNB and gNB) between the UE and the LTE core network. The traffic over diverse paths may experience different delay since the conditions are generally different (e.g., due to wireless channel, background traffic). Therefore, one of the most important problems in efficient operation with DC is minimizing the end-to-end delay considering all the connections. To address that problem, we adopt the deterministic network calculus to first characterize the delay experienced by each connection; then to model the overall end-to- end delay in the 5G small cell. We then formulate an optimization problem that attempts to find the optimal traffic splitting over the connections while minimizing the delay. We derive the solution for the problem, as well as, present the numerical results.

Dividing the transmission power statically among Long Term Evolution (LTE) and New Radio (NR) carriers during dual connectivity may result in a great deal of unused power, which may lower the throughput and user experience. RAN4 has mandated the need for Dynamic Power Sharing (DPS) for all the User Equipments (UEs) supporting LTE-NR dual connectivity. DPS allows the UE to distribute the transmit power among carriers. However, optimizing the power distribution among the LTE and NR carriers during dual connectivity efficiently and effectively is still an open problem. In this paper, we propose a novel distributed Q-learning assisted DPS scheme to learn the distribution of transmission powers for LTE and NR carriers for dual connectivity. Extensive simulations and analysis reveal that our proposed scheme improves the network performance by allocating transmission powers optimistically considering channel fluctuations.

In the next generation (5G) new radio (NR) systems, beamforming is an enabling technology for millimeter wave communications which require beam sweeping for transmission. When user equipment (UE) uses discontinuous reception (DRX) to save power, the UE may be informed of incoming services or updating system information through a paging procedure. A next generation NodeB (gNB) transmits the same paging message on multiple beams in discrete time slots to notify the target UE. As the paging is transmitted through beam sweeping, paging transmission occupies multiple time slots and the resources in paging occasion. Additionally, increasing number of time slots make the UE wake up longer to monitor the paging occasion, and this directly increases the power consumption of the UE. In this paper, we propose an efficient beam sweeping paging mechanism taking beam sweeping overhead and UE power consumption into consideration. Mathematical analysis and simulation experiments show that the proposed mechanism enhances the performance of power saving while reducing the overhead of paging sweeping beams.

NR5G dual connectivity (DC) with control/user (C/U)-plan split is the best capacity enhancing approach for high-speed users. In this work, we present DC-architecture with non-standalone (NSA) model of 5G network in which we consider LTE evolved Node Base station (eNBs) as macro base station and NR5G next-generation node Base station (gNBs) as micro base station. These macro eNB and micro gNBs are responsible for C/U-plan traffics respectively, so called EUTRAN(LTE)-NR5G dual connectivity (ENDC). We analyze the transition of C-plane or D-plane from the source network to the target network in the proposed HetNet i.e., Control-Plane Handoffs (CPHO), User-Plane Handoffs (UPHO). we evaluate the performance of ENDC C/U plan split in the shadowing environment for various range of user equipment (UE) velocities.KeywordsNR5G HetNetDual connectivity (DC)C/U-Plane splitControl Plane Handoffs (CPHO)User Plane Handoffs (UPHO)User Equipment (UE)eNB and gNB

In this paper traffic steering between a High-Speed Downlink Packet Access (HSDPA) network and a 3GPP Long Term Evolution (LTE) network with different carrier frequencies is investigated. First, two traffic steering algorithms, relying on static network information, are assessed from a traffic theoretical point of view and numerically. Furthermore, numerical analysis of two traffic steering algorithms, relying on dynamic information such as user SINR and cell load, is also performed. It is shown that the dynamic traffic steering algorithms outperform the static methods in terms of end user performance. Finally, it is investigated how the LTE terminal penetration affects the performance of the proposed traffic steering algorithms. For low LTE terminal penetration all LTE capable terminals should be pushed to the LTE network, and for high LTE terminal penetration a more dynamic traffic steering scheme should be used.

The high throughput with low latency, massively connected devices, and effective utilization of spectrum for current wireless communication systems can be realized by adopting the fifth-generation (5G) new radio (NR) air interface. The key remarkable features that 5G NR presents are Ultra-Reliable Low-Latency Communications (URLLC), enhanced Mobile Broadband (eMBB), and massive Machine Type Communications (mMTC). To meet thereof features, 5G NR exerts different multiple access and modulation techniques. This paper addresses the physical layer of 5G NR and more explicitly explores the transmission of 5G NR over the physical uplink shared channel (PUSCH) considering several parameters. For example, different sub-carrier spacings (SCSs) are taken into account for analyzing the performance of PUSCH in terms of throughput versus Signal-to-Noise Ratio (SNR). Moreover, the effect of the well-known modulation techniques such as Quadrature Phase Shift Keying (QPSK), different order of Quadrature Amplitude Modulation (QAM) (i.e., 16, 64, and 256) on throughput is studied. Later on, the number of base station (BS) and user equipment (UE) antennas are varied. Lastly, the performance of PUSCH over different propagation channel models (clustered delay line (CDL) and tap delay line (TDL)) is also investigated in this paper. The extensive simulation studies have proved that QPSK exhibits finer outcomes in low SNR regions while 256-QAM shows remarkable results in high SNR regions. The maximum throughput can be realized even in low SNR regime if the number of BS antennas is increased. In addition, high throughput value can be attained by increasing SCS.

Bandwidth Parts (BWPs) is a 5G New Radio (NR) Release 15 feature introduced for dynamically adapting the carrier bandwidth and numerology in which a User Equipment (UE) operates. In 4G/LTE, UEs support the maximum possible bandwidth of 20MHz. In 5G, the operating bandwidth can be as high as 800MHz per carrier. Each UE cannot support such a high bandwidth without high-power consumption. Therefore, a 5G UE has to communicate on a bandwidth smaller than the cell’s channel bandwidth. The smaller part is referred to as BWP. BWP enables higher spectrum flexibility with reduced baseband processing and power savings. BWP selection (or BWP switching) can be performed through several different methods. bwp-InactivityTimer is one of the methods or techniques to switch BWP. BWP switching is always associated with switch delay. Frequent BWP switching directly impacts latency and system throughput. In NR, new gap patterns with larger gap lengths of 40 ms and 66 ms features are implemented for accurate positioning measurements. The effect of bwp-InactivityTimer during larger measurement gaps and associated delays have not been studied and understood thoroughly for bursty traffic. Trade-offs must be carefully considered between energy efficiency and other performance aspects such as latency, throughput, and so on. In this paper, we propose an Efficient BWP Switch Method (EBSM) novel algorithm to handle bwp-InactivityTimer to reduce latency and thereby increase the system throughput during larger gap lengths configured for accurate positioning measurements. Simulation results show that the proposed EBSM algorithm is on average 29.8% more efficient in shortening latency and around 15-52% more efficient in avoiding unnecessary BWP switching in comparison with the specification-defined current legacy method.

5G New Radio (NR) is the 3rd Generation Partnership Project (3GPP) radio access technology for the next generation mobile communications network. A major evolution of 5G constitutes the integration of non-terrestrial networks including geostationary and low Earth orbit satellites. The seamless integration of satellites in the terrestrial mobile network requires significant adaptations within the radio access network and the development of new features in the core network to cope with the specific satellite channel characteristics. To date, the 5G control and data plane has been standardized to handle only continuous backhaul communication between the network components. However, a mobile satellite enabled next generation Node B (gNB) located in a vehicle or in a moving aerial platform needs to be able to handle frequent backhaul outages of various duration as well as longer signal delays as opposed to short terrestrial connections via fiber. In this paper, we report the results of an over-the-air (OTA) field trial comprising a mobile edge node connected to the 5G standalone core network components over a geostationary satellite. We analyze Transmission Control Protocol (TCP) acceleration and GPRS Tunneling Protocol (GTP)/TCP/Internet Protocol (IP) header compression features through the GTP. Moreover, the influence of short and long interruptions in the communication between the edge node and the central components on the entire system performance is investigated. The header compression and TCP acceleration modules were implemented on the satellite modems and are now part of the protocol stack of these devices. The results show up to 12% higher data rates for the 5G user equipment (UE), on a 1.5 MHz single carrier return link compared to deactivated TCP acceleration and header compression. We increased the data rate by 20% on the 4.5 MHz DVB-S2X forward link between the UE and 5G core. Moreover, our measurements reveal that even satellite-enabled gNB mobility is possible with the current Release 15 standard. After a short outage of the satellite connection due to shadowing, the UE can successfully re-establish the user plane connection to the core network. Our results will facilitate the full integration of satellite components in 5G through open and standard solutions.

Improving energy efficiency and extending the lifetime of User Equipment (UE) batteries are among the key performance requirements for the Fifth-Generation (5G) network goals. To realize these goals, ongoing studies are developing schemes to improve both performance requirements. One of the mechanisms at the forefront of these studies is Discontinuous Reception (DRX). This mechanism, which was inherited from the Fourth-Generation (4G) wireless network is crucial, as its performance with regard to the performance requirements for 5G goals has a great impact on the user's satisfaction. Although the DRX mechanism is adapted to meet the power-saving need of a 5G wireless network, the energy expenses for operations at millimetre-wave frequencies are still of concern. In this paper, recent research solutions that consider the application of the DRX mechanism in association with key enabling features and factors such as paging, RRC_INACTIVE, mmWave, and UE mobility are discussed for 5G use cases. In addition, the effect of these features and factors is considered, as well as recent solutions to address the challenges identified. Simulation results of this approach showed an average of 399mW of power consumed in a 24-hour period, which represents a 6% mean percentage reduction in UE power consumption when compared to the existing scheme.

SummaryFifth‐generation (5G) networks deal with high‐frequency data rates, ultra‐low latency, more reliability, massive network capacity, more availability, and a more uniform user experience. To validate the high‐frequency rates, 5G networks engage beam searching operation. By adopting a beam searching state between the short and long sleep, one can reduce the system's delay. The energy consumption of user equipment (UE) in 5G networks is much higher than in the 4G networks. To reduce the energy consumption and increase the energy saving in UE, Long‐Term Evolution (LTE)‐5G networks adopt the discontinuous reception (DRX) scheme with a fixed number of short sleep. LTE‐DRX without beam search operation (i.e., beam alignment) cannot work in 5G networks. Hence, keeping this scenario in mind, we have modeled a new modified directional discontinuous reception (MD‐DRX) mechanism for LTE‐5G networks. The MD‐DRX mechanism captures the behavior of a beam searching, an inactive, an active, a long sleep, an ON, and a short sleep states. The short sleep state consists of a maximum short sleep. To get the optimal energy saving and energy consumption (i.e., energy efficiency) from the MD‐DRX mechanism, it is required to check the system's throughput. The trade‐off between energy saving/energy consumption and throughput will provide the system's optimal energy saving and optimal energy consumption. In this paper, we have obtained the system's optimal energy saving and throughput by optimizing the maximum short sleep and short sleep duration. To get the energy efficiency for LTE‐5G networks, the trade‐off between average energy consumption/energy saving and throughput is shown.

Beam management (BM) is a key component in fifth generation (5G), 5G-Advanced, and sixth generation (6G) millimeter-wave (mmWave) operations. Due to mobility or rotation of user equipment (UE), frequent beam measurements and search are needed at the UE based on also frequently transmitted reference signals (RSs). To enable mmWave BM with lower power consumed at the UE and less RS overhead, this paper proposes a machine learning (ML) assisted beam change prediction scheme based on long short-term memory (LSTM) facilitated models. Particularly, the ML-models are equipped at base station (BS) and use time series of UE reported beam qualities as inputs, which are based on the latest 3rd Generation Partnership Project (3GPP)5G new radio (NR) standards. The model outputs prediction on whether the strongest beam will be different from the currently reported one until the next applicable measurement occasion. This allows the system to operate with an extended beam measurement cycle greater than commercially popular ones with very limited beam mismatch errors. Our proposed ML-models are trained and tested via data collected using a cellphone equipped with Snapdragon 5G-mmWave Modem chipset and a prototype BS, both compliant with 3GPP Release-15 5G standards. Evaluation results show that the proposed scheme can accurately predict beam change instances and reduce over half of the power consumed at the UE for BM, which also demonstrate feasibility of ML based BM for 5GAdvanced and 6G communications.

Purpose of software-defined radio (SDR) network positioning technology design is substantiation and experimental validation of new technical solutions for user equipment (UE) location estimation improvement, using infrastructure of existing 4G Long-Term Evolution (LTE) and emerging 5G New Radio (NR) networks, which is highly relevant in Global Navigation Satellite System (GNSS) denied urban environments. Approach for experimental validation is prototyping of eNodeB (eNB) reference signals transmission and UE reception procedures using SDR testbed with Universal Software Radio Peripheral (USRP) hardware and Matlab software. Generation and transmission of reference signals, performed by eNB on the physical layer, is defined by 3GPP technical specification 36.211, and receiver processing procedures, performed by UE, and strongly affecting the accuracy of primary measurements, can be designed as a proprietary solution. Findings of current research include formalization, software realization and results of experimental validation of a sequence of procedures for receiving and processing LTE reference signals in order to collect primary range-difference measurements on the UE side for observed time difference of arrival (OTDOA) positioning with developed SDR testbed. Research and development campaign on the current stage has limitation of SDR testbed validation only in laboratory conditions. Practical implications of developed UE SDR testbed allow to proceed campaign to the field conditions and test proposed technical solution with ambient LTE signals.

The recommended bit rate (RBR) is assigned by gNodeB to the user equipment (UE) using MAC control element (CE) entity to provide bit rate information in 5G New Radio (NR). At the UE, the bit rate information is passed on to the upper layers; i.e., transport or application, for a specific logical channel either in uplink or downlink. However, based on specific application rate of target, UE does not know how to efficiently utilize and distribute RBR/throughput in lower and upper layer, respectively considering the specific logical channel. To address these problems, we propose a cross layer rate adaptation (CLRA) mechanism for UE. CLRA consists of two parts. In the first part, CLRA utilizes RBR received from gNodeB to compute throughput at lower layer. In the second part, CLRA distributes the throughput in upper layer received from lower layer based on specific applications rate of target. CLRA provides an intelligent mechanism to distribute throughput among foreground/ background applications and voice over internet protocol (VoIP) application considering a learning based codec adaptation. We conduct experiments with Samsung Galaxy S8 device and simulations to validate CLRA mechanism for applications in 5G NR.

The fifth-generation mobile network has been developed and standardized with an intention of exploring the market beyond 2017. The question was to study the distribution strategies to fill out the needs of this strong network introduced for real-time feedback. Mobile operators proposed five alternative network architectures to 3GPP. The response to the question was to carry out the first distribution strategy which is Non-Standalone New Radio (NSA NR) in 2017 followed by a Standalone New Radio access network that was standardized in 2018. This study analyzes the distribution strategies of the 5G New Radio (NR) network, main technologies, benefits and drawbacks and compares NSA NR and SA NR distribution modes in terms of coverage, network capability, the inter-working which is between 4G and 5G, complexity and network distribution cost in Rwanda. This also highlights the potential challenges to implement 5G especially in Least Developed Countries. Micro Operators have been also used to accelerate the deployment for new entries and presented some challenges where the proposed solution for them has been the planification of a huge amount of economic resources as well as skilled manpower. The study concluded that the reliable and efficient distribution strategies of 5G NR Networks will be based on Non-Standalone (NSA), Standalone (SA) and the Micro Operators considerations to accelerate its distribution not only in global context but also in Rwanda