Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks

Soaring capacity and coverage demands dictate that future cellular networks need to soon migrate towards ultra-dense networks. However, network densification comes with a host of challenges that include compromised energy efficiency, complex interference management, cumbersome mobility management, burdensome signaling overheads and higher backhaul costs. Interestingly, most of the problems, that beleaguer network densification, stem from legacy networks' one common feature i.e., tight coupling between the control and data planes regardless of their degree of heterogeneity and cell density. Consequently, in wake of 5G, control and data planes separation architecture (SARC) has recently been conceived as a promising paradigm that has potential to address most of aforementioned challenges. In this article, we review various proposals that have been presented in literature so far to enable SARC. More specifically, we analyze how and to what degree various SARC proposals address the four main challenges in network densification namely: energy efficiency, system level capacity maximization, interference management and mobility management. We then focus on two salient features of future cellular networks that have not yet been adapted in legacy networks at wide scale and thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and device-to-device (D2D) communications. After providing necessary background on CoMP and D2D, we analyze how SARC can particularly act as a major enabler for CoMP and D2D in context of 5G. This article thus serves as both a tutorial as well as an up to date survey on SARC, CoMP and D2D. Most importantly, the article provides an extensive outlook of challenges and opportunities that lie at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201

Energy efficient hybrid satellite terrestrial 5G networks with software defined features

In order to improve the manageability and adaptability of future 5G wireless networks, the software orchestration mechanism, named software defined networking (SDN) with Control and User plane (C/U-plane) decoupling, has become one of the most promising key techniques. Based on these features, the hybrid satellite terrestrial network is expected to support flexible and customized resource scheduling for both massive machinetype- communication (MTC) and high-quality multimedia requests while achieving broader global coverage, larger capacity and lower power consumption. In this paper, an end-to-end hybrid satellite terrestrial network is proposed and the performance metrics, e. g., coverage probability, spectral and energy efficiency (SE and EE), are analysed in both sparse networks and ultra-dense networks. The fundamental relationship between SE and EE is investigated, considering the overhead costs, fronthaul of the gateway (GW), density of small cells (SCs) and multiple quality-ofservice (QoS) requirements. Numerical results show that compared with current LTE networks, the hybrid system with C/U split can achieve approximately 40% and 80% EE improvement in sparse and ultra-dense networks respectively, and greatly enhance the coverage. Various resource management schemes, bandwidth allocation methods, and on-off approaches are compared, and the applications of the satellite in future 5G networks with software defined features are proposed

Adaptive data synchronization algorithm for IoT-oriented low-power wide-area networks

The Internet of Things (IoT) is by now very close to be realized, leading the world towards a new technological era where people’s lives and habits will be definitively revolutionized. Furthermore, the incoming 5G technology promises significant enhancements concerning the Quality of Service (QoS) in mobile communications. Having billions of devices simultaneously connected has opened new challenges about network management and data exchange rules that need to be tailored to the characteristics of the considered scenario. A large part of the IoT market is pointing to Low-Power Wide-Area Networks (LPWANs) representing the infrastructure for several applications having energy saving as a mandatory goal besides other aspects of QoS. In this context, we propose a low-power IoT-oriented file synchronization protocol that, by dynamically optimizing the amount of data to be transferred, limits the device level of interaction within the network, therefore extending the battery life. This protocol can be adopted with different Layer 2 technologies and provides energy savings at the IoT device level that can be exploited by different applications

Performance Comparison Between VoLTE and non-VoLTE Voice Calls During Mobility in Commercial Deployment: A Drive Test-Based Analysis

The optimization of network performance is vital for the delivery of services using standard cellular technologies for mobile communications. Call setup delay and User Equipment (UE) battery savings significantly influence network performance. Improving these factors is vital for ensuring optimal service delivery. In comparison to traditional circuit-switched voice calls, VoLTE (Voice over LTE) technology offers faster call setup durations and better battery-saving performance. To validate these claims, a drive test was carried out using the XCAL drive test tool to collect real-time network parameter details in VoLTE and non-VoLTE voice calls. The findings highlight the analysis of real-time network characteristics, such as the call setup delay calculation, battery-saving performance, and DRX mechanism. The study contributes to the understanding of network optimization strategies and provides insights for enhancing the quality of service (QoS) in mobile communication networks. Examining VoLTE and non-VoLTE operations, this research highlights the substantial energy savings obtained by VoLTE. Specifically, VoLTE saves approximately 60.76% of energy before the Service Request and approximately 38.97% of energy after the Service Request. Moreover, VoLTE to VoLTE calls have a 72.6% faster call setup delay than non-VoLTE-based LTE to LTE calls, because of fewer signaling messages required. Furthermore, as compared to non-VoLTE to non-VoLTE calls, VoLTE to non-VoLTE calls offer an 18.6% faster call setup delay. These results showcase the performance advantages of VoLTE and reinforce its potential for offering better services in wireless communication networks.Comment: Accepted for presentation and Publication on the IEEE 10th International Conference on Electrical Engineering, Computer Science and Informatics (EECSI 2023

On feasibility of the UE power saving signal for the 5G new radio

Abstract. The objective of this thesis is to study and evaluate physical layer signals and channels to achieve the user equipment (UE) power saving in the 3rd generation partnership project (3GPP) new radio (NR). The fifth generation (5G) mobile network has strict objectives regarding power consumption and performance. The UE power consumption also has a big impact on the end user’s quality of experience (QoE) and future deployment of NR devices. Therefore, it is very important to study ways to reduce UE power consumption. One feasible power saving technique is the usage of so-called power saving signal or channel, which triggers the UE to transition to the active mode from the power saving mode. The first part of this work provides an overview of general properties of the NR and its physical downlink signals and channels, as well as the UE operation and power consumption in the connected mode. Then, examples of existing power saving techniques are discussed and a new scheme of the wake-up mechanism and the UE power saving signal/wake-up signal (WUS) is described. Lastly, different design options for the power saving signal are described and their detection performance is studied. The power saving signal options of this thesis can be divided into physical downlink control channel (PDCCH) based and sequence-based signals/channels. In the PDCCH based option, the power saving indication is carried as a payload of the PDCCH. Studied sequence-based options are the secondary synchronization signal (SSS), the PDCCH demodulation reference signal (DMRS), the channel state information reference signal (CSI-RS) and a UE-specific sequence that is mapped to all radio resources allocated for the PDCCH. The detection of the latter is done in time domain, and the detection of the other sequences is done in frequency domain. The detection performance of these signals/channels is compared based on link-level simulation results. Simulations were done with a Matlab-based simulator. They show the impact of the frequency- and time-selectivity and implementation impairments. Based on the numerical results, the impact of the UE speed up to 120 km/h and the carrier frequency offset (CFO) up to 400 Hz can be neglected with all the options except CSI-RS. It was shown that the sequence-based WUS options tend to suffer from the frequency-selective radio channel. By making decisions within the channel’s coherence bandwidth and using precoder cycling, the negative impact of the channel can be reduced. With these techniques, PDCCH DMRS outperforms all the other sequence-based options. However, in terms of detection performance, the PDCCH based power saving signal/channel is the most robust option of this set of candidates.Päätelaitteen virransäästösignaalin soveltuvuus 5G:n uuteen radiorajapintaan. Tiivistelmä. Tämän diplomityön tavoitteena on tutkia ja verrata fyysisen kerroksen signaaleja, päätelaitteen (user equipment, UE) virransäästön toteuttamiseksi 3GPP:n uudessa radiorajapinnassa (New Radio, NR). Viidennen sukupolven (5th generation, 5G) mobiiliverkolla on tiukat tavoitteet virransäästön ja suorituskyvyn osalta. Päätelaitteen virrankulutuksella on myös suuri vaikutus loppukäyttäjän kokemukseen ja tulevien NR-laitteiden käyttöönottoon. Siksi onkin erittäin tärkeää tutkia mahdollisia tapoja vähentää päätelaitteen virrankulutusta. Yksi mahdollinen virransäästötekniikka on niin sanottu virransäästösignaali, joka herättää päätelaitteen virransäästötilasta verkkoyhteyteen. Työn ensimmäinen osa käsittelee NR:n yleisiä ominaisuuksia, alalinkin fyysisiä signaaleja ja kanavia, sekä päätelaitteen virrankulutusta verkkoyhteydessä. Seuraavaksi käsitellään olemassa olevia virransäästötekniikoita, sekä käydään läpi uutta herätys-tyyppistä mekanismia ja päätelaitteen virransäästösignaalin/herätyssignaalin (wake-up signal, WUS) toimintaa. Lopuksi kuvataan erilaisia virransäästösignaalivaihtoehtoja ja tutkitaan niiden havaitsemisen suorituskykyä. Työn virransäästösignaalivaihtoehdot voidaan jakaa alalinkin kontrollikanava- (physical downlink control channel, PDCCH) ja sekvenssipohjaisiin signaaleihin/kanaviin. PDCCH-pohjaisessa vaihtoehdossa virransäästösignaali siirretään PDCCH:n hyötykuormana. Tutkitut sekvenssipohjaiset vaihtoehdot ovat toissijainen synkronointisignaali (secondary synchronization signal, SSS), PDCCH-demodulaatio-referenssisignaali (demodulation reference signal, DMRS), kanavan tilatieto-referenssisignaali (channel-state information reference signal, CSI-RS), sekä UE-spesifinen sekvenssi, joka asetetaan PDCCH:n jokaiseen alikantoaaltoon. Jälkimmäisen havaitseminen tehdään aikatasossa ja muiden sekvenssien havaitseminen tehdään taajuustasossa. Näiden signaalien/kanavien havaitsemisen suorituskykyä vertaillaan linkkitason simulointitulosten perusteella. Simulaatiot tehtiin Matlab-pohjaisella simulaattorilla. Ne esittävät aika- ja taajuusselektiivisyyden, sekä toteutuksen epäideaalisuuksien vaikutusta. Numeeristen tulosten perusteella, UE:n nopeus arvoon 120 km/h ja kantoaaltotaajuussiirto (carrier frequency offset, CFO) 400 Hz:iin asti voidaan jättää huomioimatta, kaikkien muiden paitsi CSI-RS:n tapauksessa. Työssä osoitettiin, että sekvenssipohjaiset WUS-vaihtoehdot kärsivät taajuusselektiivisestä radiokanavasta. Kanavan negatiivista vaikutusta voidaan pienentää tekemällä päätöksiä kanavan koherenssikaistanleveyttä pienemmissä osissa, sekä käyttämällä syklistä esikooderia. Näillä tekniikoilla PDCCH DMRS suoriutuu kaikkia muita sekvenssipohjaisia vaihtoehtoja paremmin. Kuitenkin, havaitsemisen suorituskyvyn perusteella PDCCH-pohjainen virransäästösignaali/kanava on vahvin ehdokas näistä vaihtoehdoista