Browsing by Department "Huawei Technologies Sweden AB"

Now showing 1 - 7 of 7
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    Handover Performance and Power Consumption Analysis of LTE Mobile Relays
    (2020-11) Tayyab, Muhammad; Koudouridis, G. P.; Gelabert, X.; Jantti, R.; Department of Communications and Networking; Huawei Technologies Sweden AB
    Mobile relay node (MRN) is one of the cheaper options for reliable communication when users are moving by public transport (i.e. bus, tram, train, subway, etc.), especially in urban areas. Critically, MRNs need to maintain a backhaul connection with the fixed infrastructure via a donor eNB, (DeNB). If the MRN fails to successfully handover (HO) from one DeNB to another, it will create a single point of failure, i.e. the connection of all UEs connected to MRN will be dropped. In this paper, we address the HO performance of a MRN including a power consumption analysis thereof. We investigate the potential gains in terms of HO rate, HO failure ratio (HOFR), ping-pong (PP) rate and power consumption (both at UE and eNB) when a MRN is deployed on a bus traveling along the cell edges of surrounding macro BSs. We also look over the MRN HO failure cases to identify the causes of HO failures that are more critical for the UEs onboard. Numerical results indicate that deploying a MRN on the roof-top of a bus improves the HO rates 15%, HOFR 8%, PP rate 17%, UE power consumption 21%, and eNB power consumption 14% on average for all simulated cases. We have also established that UL transmission errors are the most dominant causes of turning MRN to a single point of failure during a HO.
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    Near-Field Beamforming for Large Intelligent Surfaces
    (2022) Hu, Sha; Ilter, Mehmet C.; Wang, Hao; Huawei Technologies Sweden AB; Risto Wichman Group; Huawei Technologies Co., Ltd.
    In this paper, we propose a novel near-field beamforming (BF) design with a Large Intelligent Surface (LIS) that is implemented as a discretized 2D-array. We first investigate the definitions of the near-field and far-field regions, and determine the Fraunhofer distance of the LIS, which scales up linearly in the surface-area of the LIS. Hence, a user-equipment (UE) can enter the near-field of a LIS in practice. In addition to Fraunhofer distance, we further derive the Fresnel near-field region where both amplitude and angle variations are negligible, as long as the distance from the UE to the LIS is larger than a threshold, which only scales up linearly in the diameter of LIS. Therefore, in the majority region of near-field, only phase variations worsen the the quality of received signal and result in significant array-gain losses. Motivated by this observation, we further propose a two-step near-field BF design that can effectively recover the array-gain losses in Fresnel near-field, and is fully compatiblewith a conventional far-field BF.
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    Receiver Power Consumption during Handover in LTE
    (2019) Tayyab, Muhammad; Koudouridis, G. P.; Gelaberr, X.; Jäntti, Riku; Department of Communications and Networking; Huawei Technologies Sweden AB
    Recently, handover (HO) has gathered huge interest as the cellular mobile users desire for better quality of service (QoS) and continuous connection has increased. The power consumption is increasing day by day due to growing data rate demands of the users that directly impacts operators' operational expenditures (OPEX) and, not least, the environment by increased CO2 emissions. In this paper, we address the power consumption caused by the air-interface signaling messages received at both the eNB and User Equipment (UE) during HO in a Long Term Evolution (LTE) cellular network. A receiver power consumption model is presented with a detailed quantitative analysis using system level simulations. Numerical results indicate that the largest contributor to received air-interface HO signaling overhead is the reception of the measurement report by the eNB.
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    A Simulation Study on Handover in LTE Ultra-Small Cell Deployment: A 5G Challenge
    (2019) Tayyab, Muhammad; Gelabert, Xavier; Jäntti, Riku; Department of Communications and Networking; Huawei Technologies Sweden AB
    Future cellular networks need to support data hungry applications with enhanced data rates possibly via cell densification (ultra-small cells). The key objective of this work is to study the performance of a cellular network by taking into account the user mobility when LTE ultra-small cell network is deployed. Handover (HO) issues are analyzed considering various cell sizes, user speeds, and HO optimization related parameters. This study is very helpful to realize the problem of HO in 5G standalone network deployment as it shows the impact of LTE ultra-small cell deployment on the HO performance. A system level simulator is used to perform simulation and the results show that, as expected, the ultra-densification results in an increased number of HOs. Also, increasing the offset values have a significant impact on the HO reliability while changing the Time to Trigger (TTT) values has a less-significant impact.
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    A Survey on Handover Management: From LTE to NR
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019) Tayyab, Muhammad; Gelabert, Xavier; Jäntti, Riku; Department of Communications and Networking; Huawei Technologies Sweden AB
    To satisfy the high data demands in future cellular networks, an ultra-densification approach is introduced to shrink the coverage of base station (BS) and improve the frequency reuse. The gain in capacity is expected but at the expense of increased interference, frequent handovers (HOs), increased HO failure (HOF) rates, increased HO delays, increase in ping pong rate, high energy consumption, increased overheads due to frequent HO, high packet losses and bad user experience mostly in high-speed user equipment (UE) scenarios. This paper presents the general concepts of radio access mobility in cellular networks with possible challenges and current research focus. In this article, we provide an overview of HO management in long-term evolution (LTE) and 5G new radio (NR) to highlight the main differences in basic HO scenarios. A detailed literature survey on radio access mobility in LTE, heterogeneous networks (HetNets) and NR is provided. In addition, this paper suggests HO management challenges and enhancingtechniques with a discussion on the key points that need to be considered in formulating an efficient HO scheme.
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    Uplink Reference Signal Based Handover with Mobile Relay Node Assisted User Clustering
    (2020-12) Tayyab, Muhammad; Koudouridis, G. P.; Gelabert, X.; Jantti, R.; Huawei Technologies; Huawei Technologies Sweden AB; Department of Communications and Networking
    In today's cellular networks, an increasing number of connected devices on-board in fast-moving vehicles would require more efficient handover (HO) procedures. To this end, we investigate the utilization of mobile relay nodes (MRNs) in vehicles to facilitate efficient HO and HO-related power consumption reductions for all on-board user equipments (UEs). In particular, the potential gains in terms of HO rate, HO failure ratio (HOFR), ping-pong (PP) rate, and total power consumption are studied for different UE cluster sizes. To eliminate the measurement power-consuming procedure, uplink (UL) reference signals (RS) transmitted by UEs are exploited. Four different case scenarios are simulated utilizing both the DL and UL RS based HO procedure, with and without deploying MRNs on the buses traveling along the cell edges of surrounding macro BSs. Simulation results indicate that the UL RS based HO procedure can improve HO performance significantly because it reduces the air-interface signaling messages, namely the measurement report (MeasReport) transmission and reception. Also, in terms of power consumption, deploying MRNs is a more attractive solution with substantial power reduction for onboard UEs of higher cluster size.
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    Uplink Reference Signals for Energy-Efficient Handover
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020) Tayyab, Muhammad; Koudouridis, George P.; Gelabert, Xavier; Jäntti, Riku; Department of Communications and Networking; Huawei Technologies Sweden AB
    The ever-growing data rate demand from cellular users increases the associated power consumption that directly contributes to the global warming of the environment. Also, achieving high system capacity by increasing the density of the base stations (BSs) increases the number of handovers (HOs) which for moderate-to-high-speed users implies significant signaling traffic overhead. One of the key research objectives of this paper is to identify the different signaling overheads occurring during the HO procedure in current 3GPP cellular networks (e.g. Long Term Evolution (LTE)/ New Radio (NR)) and, among those, which are the main contributors to power consumption. Specifically, we analyze the impact of signaling messages transmitted and received during HO on the power consumption for both the BS and the User Equipment (UE). System-level simulations are performed for a detailed quantitative analysis. Our analysis shows that the transmission of the measurement reports is the largest contributor to air-interface signaling and that its contributed total power consumption is higher than the random access channel (RACH) signaling and the signaling confirming the HO. To eliminate measurement reports and effectively reduce the power consumption associated with the HO in future networks, we propose a HO procedure that exploits uplink (UL) reference signals (RSs), namely the sounding reference signal (SRS), transmitted by UEs. The numerical results show that the proposed SRS-based method reduces the total power consumption during the HO procedure by 30% in comparison to the legacy downlink RS based measurement method in current cellular networks. Also, this method improves the UE battery lifetime by reducing the RS transmissions and measurements significantly, UE transmitted power consumption by 48% and received power consumption by 27%.