Energy-Efficient Mobility for Small-Cell Overlaid Cellular Networks

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Journal ISSN
Volume Title
School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2021-05-04
Date
2021
Major/Subject
Mcode
Degree programme
Language
en
Pages
102 + app. 126
Series
Aalto University publication series DOCTORAL DISSERTATIONS, 43/2021
Abstract
To satisfy the ever-growing demand for enhanced data rate in future cellular networks, an ultra-densification approach is introduced to shrink the coverage of base stations (BSs) and improve frequency reuse. A gain in system capacity is anticipated by increasing the density of BSs; however this gain is expected to come at the expense of a high number of handovers (HOs), increased HO delays, increased HO failures (HOFs), and a high ping pong (PP) rate, which for moderate-to-high-speed users implies significant signaling overhead traffic resulting in an unsatisfactory user experience.In this thesis, we provide a simulation analysis to study the performance of current 3GPP cellular networks (e.g. Long Term Evolution (LTE)/ New Radio (NR)) with a legacy downlink handover (DL-HO) procedure by taking into account the cell sizes and user mobility. In particular, the potential problems of HOFs are highlighted especially in the case of ultra-densification. Moreover, this work derives a power consumption model and addresses the signaling overhead and power consumption that results from the transmission and reception of HO signaling both at the BS and at the User Equipment (UE) during DL-HO. The DL-HO analysis exhibits that the measurement report (MeasReport) transmission is the largest contributor to air-interface signaling and its power consumption is higher than random access channel (RACH) signaling and the signaling confirming the HO. In order to cope with the problem of high MeasReport signaling and effectively reduce the associated power consumption, a handover that is based on the uplink (UL) reference signal, referred to here as UL-HO, is proposed that exploits uplink (UL) reference signals (RSs), namely the sounding reference signal (SRS), transmitted by UEs. The performance of UL-HO is compared with DL-HO to quantify the potential benefits in terms of reduction in HO rates, HOFs, PPs, UE, and BS power consumption. After this, we then highlight another major challenge of today's cellular networks which is the increasing demand for voice and data services in fast-moving public transportation (i.e. bus, tram, train, subway, etc.), especially in urban areas. To this end, we investigate the utilization of mobile relay nodes (MRNs) in vehicles to facilitate efficient group HO and reduce the energy consumption for all on-board UEs. In this thesis, we also address the DL-HO performance of an MRN to identify the causes of MRN HOFs towards the donor BS (DBS) that are more critical for the on-board UEs.To sort out the problem of MRN HOF to the DBS, we extend the applicability of the UL-HO scheme for the MRN to eliminate the MeasReprot signaling during MRN HO to the DBS. Therefore the HO delay can be reduced, decreasing the chances of single point of failure (SPoF) and thus, uninterrupted services can be provided to on-board UEs. Moreover, we analyze the impact of on-board UE cluster size on HO performance and the associated power consumption.
Description
Supervising professor
Jäntti, Riku, Prof., Aalto University, Department of Communications and Networking, Finland
Thesis advisor
Gelabert, Xavier, Dr., Huawei Technologies Sweden AB, Sweden
Keywords
cellular networks, energy-efficiency, mobility, power consumption
Other note
Parts
  • [Publication 1]: M. Tayyab, X. Gelabert, and R. Jäntti. A Survey on Handover Management: From LTE to NR. IEEE Access Journal, Vol. 7, Issue 1, pp. 118907-118930, August 2019.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202001021034
    DOI: 10.1109/ACCESS.2019.2937405 View at publisher
  • [Publication 2]: M. Tayyab, G. P. Koudouridis, and X. Gelabert. A Simulation Study on LTE Handover and the Impact of Cell Size. Springer, Broadnets Conference 2018, LNICST 263, pp. 398-408, 2019. The accepted author manuscript of this publication is available as separate file, see Files in this item.
    DOI: 10.1007/978-3-030-05195-2_39 View at publisher
  • [Publication 3]: M. Tayyab, X. Gelabert, and R. Jäntti. A Simulation Study on Handover in LTE Ultra-Small Cell Deployment: A 5G Challenge. IEEE 5G World Forum Conference, pp. 388-392, Dresden, Germany, 2019.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202001021342
    DOI: 10.1109/5GWF.2019.8911616 View at publisher
  • [Publication 4]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Signaling Overhead and Power Consumption during Handover in LTE. IEEE Wireless Communications and Networking Conference (WCNC), Marrakech, Morocco, 2019.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202001021333
    DOI: 10.1109/WCNC.2019.8885459 View at publisher
  • [Publication 5]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Receiver Power Consumption during Handover in LTE. IEEE 5G World Forum Conference, pp. 74-79, Dresden, Germany, 2019.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202001021302
    DOI: 10.1109/5GWF.2019.8911641 View at publisher
  • [Publication 6]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Handover Performance and Power Consumption Analysis of LTE Mobile Relays. IEEE Vehicular Technology Conference (VTC) Conference, Victoria, Canada, Dec 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202103312774
    DOI: 10.1109/VTC2020-Fall49728.2020.9348720 View at publisher
  • [Publication 7]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Uplink Reference Signals for Energy-Efficient Handover. IEEE Access Journal, Vol. 8, PP. 163060-163079, September 2020.
    DOI: 10.1109/ACCESS.2020.3020618 View at publisher
  • [Publication 8]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Uplink Reference Signal Based Handover with Mobile Relay Node Assisted User Clustering. IEEE Global Communications Conference (GLOBECOM), Taipei, Taiwan, Dec.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202103312666
    DOI: 10.1109/GLOBECOM42002.2020.9322218 View at publisher
  • [Publication 9]: M. Tayyab, G. P. Koudouridis, X. Gelabert, and R. Jäntti. Uplink Reference Signals for Power Efficient Handover in Cellular Networks with Mobile Relays. IEEE Access Journal, Vol. 9, PP. 24446-24461, Feb 2021.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202103102288
    DOI: 10.1109/ACCESS.2021.3056945 View at publisher
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