Initial Access Frameworks for 3GPP NR at mmWave Frequencies

The use of millimeter wave (mmWave) frequencies for communication will be one of the innovations of the next generation of cellular mobile networks (5G). It will provide unprecedented data rates, but is highly susceptible to rapid channel variations and suffers from severe isotropic pathloss. Highly directional antennas at the transmitter and the receiver will be used to compensate for these shortcomings and achieve sufficient link budget in wide area networks. However, directionality demands precise alignment of the transmitter and the receiver beams, an operation which has important implications for control plane procedures, such as initial access, and may increase the delay of the data transmission. This paper provides a comparison of measurement frameworks for initial access in mmWave cellular networks in terms of detection accuracy, reactiveness and overhead, using parameters recently standardized by the 3GPP and a channel model based on real-world measurements. We show that the best strategy depends on the specific environment in which the nodes are deployed, and provide guidelines to characterize the optimal choice as a function of the system parameters.Comment: 8 pages, 7 figures, 3 tables, accepted to the IEEE 17th Annual Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net). arXiv admin note: substantial text overlap with arXiv:1804.0190

A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies

The millimeter wave (mmWave) frequencies offer the availability of huge bandwidths to provide unprecedented data rates to next-generation cellular mobile terminals. However, mmWave links are highly susceptible to rapid channel variations and suffer from severe free-space pathloss and atmospheric absorption. To address these challenges, the base stations and the mobile terminals will use highly directional antennas to achieve sufficient link budget in wide area networks. The consequence is the need for precise alignment of the transmitter and the receiver beams, an operation which may increase the latency of establishing a link, and has important implications for control layer procedures, such as initial access, handover and beam tracking. This tutorial provides an overview of recently proposed measurement techniques for beam and mobility management in mmWave cellular networks, and gives insights into the design of accurate, reactive and robust control schemes suitable for a 3GPP NR cellular network. We will illustrate that the best strategy depends on the specific environment in which the nodes are deployed, and give guidelines to inform the optimal choice as a function of the system parameters.Comment: 22 pages, 19 figures, 10 tables, published in IEEE Communications Surveys and Tutorials. Please cite it as M. Giordani, M. Polese, A. Roy, D. Castor and M. Zorzi, "A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies," in IEEE Communications Surveys & Tutorials, vol. 21, no. 1, pp. 173-196, First quarter 201

An Efficient Uplink Multi-Connectivity Scheme for 5G mmWave Control Plane Applications

The millimeter wave (mmWave) frequencies offer the potential of orders of magnitude increases in capacity for next-generation cellular systems. However, links in mmWave networks are susceptible to blockage and may suffer from rapid variations in quality. Connectivity to multiple cells - at mmWave and/or traditional frequencies - is considered essential for robust communication. One of the challenges in supporting multi-connectivity in mmWaves is the requirement for the network to track the direction of each link in addition to its power and timing. To address this challenge, we implement a novel uplink measurement system that, with the joint help of a local coordinator operating in the legacy band, guarantees continuous monitoring of the channel propagation conditions and allows for the design of efficient control plane applications, including handover, beam tracking and initial access. We show that an uplink-based multi-connectivity approach enables less consuming, better performing, faster and more stable cell selection and scheduling decisions with respect to a traditional downlink-based standalone scheme. Moreover, we argue that the presented framework guarantees (i) efficient tracking of the user in the presence of the channel dynamics expected at mmWaves, and (ii) fast reaction to situations in which the primary propagation path is blocked or not available.Comment: Submitted for publication in IEEE Transactions on Wireless Communications (TWC

mmWave RX interference test considerations and challenges in OTA environment

Abstract. Verifying equipment using the OTA (Over the Air) techniques is a recent addition in telecommunication testing. With the addition of new frequency bands, mmWave (millimetre wave) technology and massive MIMO (Multiple-Input-Multiple-Output), the 3GPP (3rd Generation Partnership Programme) has cemented OTA testing as the focus for verifying future equipment. However, these verifying methods are still in development, or stated as general ideas of how they are meant to be done. The main goal of this thesis is to study and design a system for receiver radio testing, according to 3GPP specifications. The test system must operate in mmWave frequency range and must be integrated to a pre-built antenna testing environment. The motivation is to verify the testing method proposed by 3GPP for mmWave receiver testing and analyse it thoroughly. This thesis aims to answer such research questions as: Is the testing method proposed by 3GPP valid for verifying mmWave frequency products? What are the major challenges, when designing test setup for high frequency devices? How can the method be improved and how it can be applied in the future? This thesis answers the first question by applying the proposed test methods in practical scenario and testing an actual eNB/gNB (eNodeB / Next generation eNodeB). Since the proposed test method has only general outline of what equipment to use, the actual test scenario will have additional pieces of testing equipment. For the second question, this thesis discusses the theory behind 5G and mmWave challenges, and how the use of these techniques is justified for practical usage. This theory is based on former research as well as current specifications applied by the 3GPP. The third research question is part of the final analysis, where the test results are analysed, and the major parts are discussed in depth. These discussions are then further expanded on with the purpose of suggesting possible areas of improvement as well as how to apply these findings into future use. The final outcome of the study is that the suggested test method is workings as it was presented by the 3GPP. However, there are some areas of improvement that should be discussed as a future work.Millimetriaaltojen RX interferenssi RF-testit OTA-ympäristössä. Tiivistelmä. Tuotteiden testaaminen ilmateitse on melko uusi lisäys tietoliikennetestauksen tekniikoihin, joita käytetään tuotteiden varmentamiseen. 3GPP on osoittanut OTA-testauksen keskeiseksi osaksi tulevien tuotteiden verifiointia. Osaksi tämä johtuu uusien taajuuskanavien käyttöönotosta, millimetriaaltoteknologiasta sekä massive MIMO tuotteiden yleistymisestä. Vaikka testaustapoja on jo ehdotettu, ne ovat vielä mahdollisesti vain yleisiä ideoita kuinka testejä tulisi suorittaa. Työn tarkoituksena on tutkia ja suunnitella vastaanottimen testaamiseen tehty testijärjestely. Testijärjestelyn tulee toimia millimetriaalloille tarkoitetulla taajuusalueella, ja työ tulee integroida valmiiksi suunniteltuun CATR-antennikammioon. Työn motivaationa on verifioida 3GPP:n ehdottama testausmetodi, millimetriaaltotaajuuksilla toimivien vastaanottimien toimivuus ja analysoida tämä tarkemmin. Tämä työ pyrkii vastaamaan tutkimuskysymyksiin kuten: Onko 3GPP:n ehdottama testimetodi pätevä verifioimaan millimetriaaltotaajuuksilla toimivia tuotteita? Mitä ovat suurimmat haasteet, kun suunnitellaan testijärjestelyä korkeataajuuksisille laitteille? Kuinka tätä metodia voidaan parantaa, ja kuinka sitä voidaan hyödyntää tulevaisuudessa? Työ vastaa ensimmäiseen tutkimuskysymykseen ottamalla käyttöön 3GPP:n ehdottamat testausmetodit käytännön testijärjestelyssä, ja testaamalla näillä metodeilla oikean tuotteen. Tällä tavoin ehdotettu testausmetodi pyritään verifioimaan. Tulee kuitenkin ottaa huomion, että ehdotetussa metodissa esitetään vain yleisellä tasolla mitä testaamiseen käytettävää laitteistoa käytetään. Tämän takia testeissä tulee olemaan joitain lisälaitteita, jotka ovat kuitenkin osa kokonaista testiympäristöä. Toiseen tutkimuskysymykseen perehdytään käymällä läpi teoriaa 5G:n ja millimetriaaltoteknologian haasteista, ja kuinka näitä tekniikoita tullaan hyödyntämään tulevaisuudessa. Teoria perustuu aiempaan tutkimukseen, sekä nykyisiin spesifikaatioihin jota 3GPP on kehittänyt. Kolmas tutkimuskysymys on osa lopullista analyysiä, jossa testien tulokset analysoidaan ja niiden pääkohdista keskustellaan tarkemmin. Tämän jälkeen keskusteluja täsmennetään liittyen mahdollisiin parannuksiin tietyllä aihealueilla, sekä mahdollisuuksista käyttää kyseisiä tuloksia tulevaisuudessa. Lopullinen päätelmä on, että ehdotettu testausmetodi toimii kuten se oli esitetty 3GPP:n dokumentoinnissa. On kuitenkin joitain osa-alueita, joita voitaisiin käsitellä tarkemmin tai jopa parantaa tulevaisuutta varten

Performance Comparison of Dual Connectivity and Hard Handover for LTE-5G Tight Integration in mmWave Cellular Networks

MmWave communications are expected to play a major role in the Fifth generation of mobile networks. They offer a potential multi-gigabit throughput and an ultra-low radio latency, but at the same time suffer from high isotropic pathloss, and a coverage area much smaller than the one of LTE macrocells. In order to address these issues, highly directional beamforming and a very high-density deployment of mmWave base stations were proposed. This Thesis aims to improve the reliability and performance of the 5G network by studying its tight and seamless integration with the current LTE cellular network. In particular, the LTE base stations can provide a coverage layer for 5G mobile terminals, because they operate on microWave frequencies, which are less sensitive to blockage and have a lower pathloss. This document is a copy of the Master's Thesis carried out by Mr. Michele Polese under the supervision of Dr. Marco Mezzavilla and Prof. Michele Zorzi. It will propose an LTE-5G tight integration architecture, based on mobile terminals' dual connectivity to LTE and 5G radio access networks, and will evaluate which are the new network procedures that will be needed to support it. Moreover, this new architecture will be implemented in the ns-3 simulator, and a thorough simulation campaign will be conducted in order to evaluate its performance, with respect to the baseline of handover between LTE and 5G.Comment: Master's Thesis carried out by Mr. Michele Polese under the supervision of Dr. Marco Mezzavilla and Prof. Michele Zorz

Millimeter-wave Evolution for 5G Cellular Networks

Triggered by the explosion of mobile traffic, 5G (5th Generation) cellular network requires evolution to increase the system rate 1000 times higher than the current systems in 10 years. Motivated by this common problem, there are several studies to integrate mm-wave access into current cellular networks as multi-band heterogeneous networks to exploit the ultra-wideband aspect of the mm-wave band. The authors of this paper have proposed comprehensive architecture of cellular networks with mm-wave access, where mm-wave small cell basestations and a conventional macro basestation are connected to Centralized-RAN (C-RAN) to effectively operate the system by enabling power efficient seamless handover as well as centralized resource control including dynamic cell structuring to match the limited coverage of mm-wave access with high traffic user locations via user-plane/control-plane splitting. In this paper, to prove the effectiveness of the proposed 5G cellular networks with mm-wave access, system level simulation is conducted by introducing an expected future traffic model, a measurement based mm-wave propagation model, and a centralized cell association algorithm by exploiting the C-RAN architecture. The numerical results show the effectiveness of the proposed network to realize 1000 times higher system rate than the current network in 10 years which is not achieved by the small cells using commonly considered 3.5 GHz band. Furthermore, the paper also gives latest status of mm-wave devices and regulations to show the feasibility of using mm-wave in the 5G systems.Comment: 17 pages, 12 figures, accepted to be published in IEICE Transactions on Communications. (Mar. 2015