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White paper coord_la_and_ec

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3GPP RAN plenary meeting #84 in Newport Beach, US, in June 2019, discussed the content of 5G New Radio (5G-NR) Release 17 standardization. One of the defined key areas for 5G enhancements for 5G enhancements is NR Broadcast / Multicast (BC/MC). Important use cases for this technology are NR Vehicle-to-Everything (V2X), NR Public Safety and NR Non-Terrestrial Networks (NTN). This white paper proposes a mechanism of link adaptation in coordination with higher layer Error Correction. A detailed description and system-level simulation-based evaluation of the proposed scheme is provided in this White Paper.

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White paper coord_la_and_ec

  1. 1. Coordinated Link Adaptation and Higher Layer Error Correc- tion for 5G Broadcast / Multi- cast July 8, 2019 Fasil Tesema, Volker Pauli NOMOR Research GmbH, Munich, Germany Summary 3GPP RAN plenary meeting #84 in New- port Beach, US, in June 2019, discussed the content of 5G New Radio (5G-NR) Release 17 standardization. One of the defined key areas for 5G enhancements for 5G enhancements is NR Broadcast / Multicast (BC/MC). Important use cases for this technology are NR Vehicle-to- Everything (V2X), NR Public Safety and NR Non-Terrestrial Networks (NTN). One area, where there is considerable room for improvement compared to LTE-based BC / MC is that of dynamic and adap- tive Radio Resource Management (RRM). Following up on previous work [1] on a second layer of Error Correction (EC) in the radio access network, this white paper proposes a mechanism of link adaptation in coordination with higher layer EC such as application layer forward error correc- tion or Layer 2 EC schemes to further im- prove spectral efficiency while maintain- ing high reliability. A detailed description and system-level simulation based evalu- ation of the proposed scheme is provided herein. I Introduction Point-to-Multipoint (PTM) transmissions are key components of wireless commu- nication to support multicast / broadcast (MC / BC) use cases that require delivery of the same content to a large number of users. While 3GPP recently decided at RAN ple- nary meeting #84 that BC / MC should be part of 5G-NR Release 17 various part- ners from academia and industry have Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 1/14
  2. 2. over the last two years been joining forces in the EU-funded project 5G-XCast fo- cused on broadcast and multicast commu- nication enablers for the fifth generation (5G) of wireless systems, and are work- ing towards providing a comprehensive so- lution to support various use cases such as multimedia, automotive (V2X), public warning systems and internet of things. In this project one of Nomor’s main tasks is to lead the studies on Radio Access Net- work (RAN) protocols and RRM for PTM transmission. At this, Nomor’s System- Level Simulator (SLS) “RealNeS” [2] is one of the primary tools for the system- level analysis and evaluation of novel con- cepts developed within the project. One of the key RRM schemes proposed and investigated via SLS is the mechanism of Link Adaptation (LA) in coordination with higher layer Error Correction (EC) schemes. This white paper presents the motivation, implementation principles and evaluation of the proposed scheme show- ing that considerable gains in sprectral ef- ficiency can be achieved while maintaining very high reliability of the BC / MC ser- vice delivery. This paper is structured as follows: Firstly, the relevant state of the art on higher layer Application Server AL-FEC Mobile Core Network Radio Access Network Point to Multi-Point wireless transmission Figure 1: Simplified diagram on the func- tional description of AL-FEC for PTM. EC schemes, link adaptation schemes for PTM and UE measurements that assist RRM is presented in Section II. Secondly, the motivation of the proposed scheme is described in Section III. Thirdly, the prin- ciple and implementation details of the proposed scheme are elaborated in Sec- tion IV. Fourthly, SLS settings and de- tailed performance evaluations are pro- vided in Section V. Finally, concluding re- marks are provided in Section VI. II State of the Art II.A AL-FEC Application Layer Forward Error Correc- tion (AL-FEC) is a method to provide ro- bustness against application layer packet losses in wireless broadcast / multicast Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 2/14
  3. 3. systems. AL-FEC is designed as a com- ponent of Content Delivery Protocols (CDPs) in the application server as shown in the simplified diagram in Figure 1. Con- tent from the application server is deliv- ered to the radio access network via the mobile core network. From there, it is wirelessly broadcasted / multicasted to re- ceiving users. The AL-FEC encoder performs block-wise encoding of source packets to generate additional repair packets that are trans- mitted at the expense of overall applica- tion layer spectral efficiency. With the help of the repair packets, the receiver application layer at the UE can recover packets lost during transmission over the wireless channel. Details on the imple- mentation of a standardized AL-FEC for LTE eMBMS can be found in [3, 4]. II.B Layer 2 EC In the 5G-Xcast project, which studies 5G broadcast / multicast solutions, a 2nd layer of EC in RAN is investigated based on the 5G-NR radio protocol architecture [1]. Herein, the encoder is embedded as part of a RAN protocol to exploit the ease of re-transmission of EC Protocol Data Units (PDUs) based on feedback requests from UEs. In this case, a code from a family of fountain codes, such as Random Linear Network Coding (RLNC) or Rap- tor codes can be used. Even though the scheme has shown a considerable benefit in terms of robustness against application layer packet losses at improved spectral efficiency, the mechanism of coordination with layer-1 link adaptation that config- ures efficient MCS settings was not inves- tigated. II.C LTE Link Adaptation for PTM Radio Bearers In the current LTE-A PTM specifica- tions, CQI-based link adaptation and re- transmission via Hybrid Automatic Repeat Request (HARQ) feedback are not used for PTM radio bearers. Proprietary im- plementation of dynamic link adaptation based on Channel Quality Indicator (CQI) feedback is possible for SC-PTM, e.g. based on the worst UE in the cell. How- ever, CQI-based link adaptations, which are also termed as inner loop link adap- tations, are observed to be inefficient for PTM bearers in the presence of several receiving UEs [5]. Based on these two restrictions, a rather conservative margin Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 3/14
  4. 4. has to be applied in selection of the Mod- ulation and Coding Scheme (MCS) lead- ing to inefficient use of radio resources. In fact, 3GPP performed a detailed study on PTM with group-based uplink feed- back for link adaptation and HARQ [5]. Herein, the HARQ feedback messages are reported from each UE to the net- work whenever a packet is received. The number of HARQ ACK/NACK messages scales with the number of UEs, leading to a high feedback load in scenarios with high number of users where PTM is typically a suitable option. Even more importantly, it is observed that the HARQ-based scheme is very inefficient as the number of UEs grows as packet loss events at different UEs are largely statistically independent such that different UEs will typically ask for retransmissions of different packets. II.D Outer Loop Link Adaptation CQI-based link adaptation is commonly termed as Inner Loop Link Adaptations (ILLA). Additionally, implementation- specific Outer Loop Link Adaptation (OLLA) techniques are typically applied for unicast to adjust the ILLA parame- ters for MCS selection in order to meet a targeted loss rate for layer-1 packets, cf. e.g. [6]. Accordingly, such OLLA schemes may for example operate based on the ratio of ACKs and NACKs received by the transmitter in response to first HARQ transmissions of a layer-1 packet. II.E UE Measurements UEs perform measurements to determine signal strength or quality of a radio link and send them in the form of UE mea- surement reports to the network. The measurement reports provide crucial infor- mation to the RAN to dynamically adapt radio resource management strategies. For 5G-NR, 3GPP has specified various UE measurements such as Synchroniza- tion Signal (SS) Reference Signal Re- ceived Power (SS-RSRP), SS Reference Signal Received Quality (SS-RSRQ), SS Signal to Interference and Noise Ratio (SS-SINR), Channel State Information RSRP (CSI-RSRP), Channel State Infor- mation RSRQ (CSI-RSRQ) and Channel State Information SINR (CSI-SINR) to collect important information about the radio link [7, 8]. These measurements are used for various RRM decisions such as UE mobility (cell selection, handover), beam management and initial access to Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 4/14
  5. 5. a network via random access procedures [7, 8, 9]. In addition to measurements on RSRP, RSRQ and SINR, 5G NR supports report- ing of further CSI information such as CQI, Precoding Matrix Indicator (PMI), Rank Indication (RI) and CSI reference signal Resource Indicator (CRI) that are used for adaptive scheduling and link adaptation. Further details can be found in [10]. III Motivation The major motivation for this work is ad- dressing the problem of RRM inefficiencies due to lack of coordination of layer 1 MCS selection and higher layer EC schemes in broadcast / multicast systems. Signal fading constitutes a major chal- lenge of wireless communication also in the context of broadcast / multicast. To address this, 3GPP has specified a 1st layer of FEC in the physical layer, Low Density Parity Check (LDPC) code for data channels and polar codes for control channel [11] in 5G “New Radio” (5G-NR), which can be readily applied also for the case of broadcast / multicast. Conventionally, broadcast / multicast in LTE networks is operated with a quite static and conservative configuration of the layer-1 MCS to provide sufficient ro- bustness against fading channel variations since ACK / NACK based error correction methods do not work well with multicast / broadcast services. For further protection against fading variation in LTE, 3GPP has specified application layer FEC (AL-FEC) based on Raptor codes in [3] as a 2nd layer EC. Herein, AL-FEC is implemented conventionally at the application servers above the UDP / IP layer introducing a statically configured amount of redun- dancy thereby allowing for less conserva- tive MCS selection in the lower layers. However, the two FEC layers (PHY/MAC and AL) are operating independently and therefore often cause a disproportionate radio resource utilization which in turn re- sults in low spectral efficiency, as well as more adverse interference situations and overall worse system performance. In [1] a 2nd layer of EC in RAN is investi- gated as higher layer EC, which can be lo- cated e.g. above or in RLC layer, wherein the redundancy of the upper EC layer is dynamically limited to a minimum that is required to avoid AL packet losses. How- ever, a mechanism of MCS selection in Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 5/14
  6. 6. coordination with 2nd layer of EC in RAN is not included there. Based on its re- lation to the Automatic Repeat reQuest (ARQ) scheme an appropriate selection of the layer-1 MCS appears to be important for high overall spectral efficiency. Hence, a mechanism for cross-layer LA that modifies MCSs at a time scale com- parable to operation of higher layer EC (such as AL-FEC or 2nd layer of EC in RAN) is indispensable in order to achieve high spectral efficiency while providing robustness that fulfills the QoE require- ments. IV Coordination of LA and Higher Layer EC This work proposes a practical coordina- tion of higher layer EC, such as AL-FEC or layer-2 EC in RAN, and link adaptation which reselects the MCS based on obser- vation of higher-layer EC PDU loss rate (PLR) performance at a rate that is slow compared to conventional link adaptation based on CQI and HARQ feedback. To this end, the network configures UEs to perform and report measurements on EC PDU PLR within a higher-layer EC opera- tional block or at an even lower rate. The higher-layer EC operational block refers to the group of Source Data Units (SDUs) over which higher layer EC is applied to generate EC PDUs. The network processes reports on PLR measurements which are received from multiple UEs. In particular, the network layer that hosts the higher layer EC makes decisions to increment or decrement the MCS based on a comparison of the re- ported EC PDU PLRs against thresh- old configured by the network, where however, for stability reasons not every comparison between current PLR value against the thresholds should trigger a change in the MCS. The objective is to keep the highest PLR of any UE that is to be served within a certain target corridor (if upper and lower PLR threshold differ) or close to a target (if both thresholds are configured equally). At this, it may of course make sense to drop some cell-edge UEs from the PTM service aiming e.g. for 95% coverage, or serving those UEs separately via a PTP connection. The MCS modification is applied via cross-layer communication between the higher layer that hosts EC and MAC layer Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 6/14
  7. 7. where the MCS modification is applied. A convenient feature of this approach apart from the main purpose of increas- ing spectral efficiency is that – even with a fixed configuration of higher-layer EC re- dundancy – adaptation based on observa- tions of non-zero EC PDU PLR samples at the higher layer is possible, as the higher- layer EC can correct some packet losses occuring in the lower layers. V Performance Evaluation In this section simulation results on co- ordination of LA and higher layer EC are presented. The system-level simulator used in this study is also being used under the um- brella of the 5G Infrastructure Association (5G-IA) to perform the IMT-2020 evalua- tion based on the ITU-R guidelines in [12]. It has been calibrated against 3GPP’s system level simulators. The calibration results can be found in [14]. Accurate spa- 1 M, N and P refer to the number of verti- cal, horizontal and polarization of elements in the antenna array, respectively. 2 The 8 vertical antenna elements for each po- larization are hard-wired and are fed by a single Transceiver Unit (TxRU). Parameter Value Carrier frequency 3.5 GHz Total BS transmit power 51 dBm Systembandwidth 100 MHz BS antenna configura- tion [M, N, P] = [8, 4, 2] 1 BS TXRU configuration [Mp, Np, P] = [1, 4, 2]2 UE antenna / TxRU configuration [M, N, P] = [1, 4, 2] Inter-site distance 200 m UE mobility model 3kmph, randomly uniform distr. BS noise figure 5 dB UE noise figure 9 dB BS ant. element gain 5 dBi BS ant. elev. 3dB-BW 65◦ BS ant. azim. 3dB-BW 65◦ BS ant. mech. downtilt 20◦ UE ant. element gain 0 dBi PTP traffic model Full buffer PTM traffic model 8Mbps, packet arrival rate 100Hz Channel model 3GPP TR 38.901 [13] Table 1: Main simulation parameters. tial channel models based on [13] are used. Of the various test environments defined for IMT-2020 evaluations [12], the dense urban test environment is used for perfor- mance evaluation in this paper. Table 1 summarizes the main simulation parameters, which are derived from the “Dense Urban” scenario. Here, link adap- tation was performed by comparing the worst EC PDU PLR reported by any UE, i.e., the coverage target was 100%. Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 7/14
  8. 8. V.A Coordination of LA and AL- FEC Herein, we compare the newly proposed mechanism of LA in coordination with AL-FEC scheme against two reference schemes: No EC: Operation without any kind of higher layer EC scheme. AL-FEC: Operation with LTE-like AL- FEC, i.e., a systematic fountain code. Deviating from the LTE specifica- tion, we use a systematic RLNC code with optimal – e.g. Gauss-Jordan elimination based – decoding. A comparison with actual Raptor codes as standardized for deployment in LTE is provided in [1]. Figure 2 shows the CDF of AL Spectral Efficiency (SE) comparing ‘no EC’, ‘AL- FEC’ (with no LA) and ‘AL-FEC+LA’. Practically, a network operator could flex- ibly configure the two thresholds men- tioned in Section IV. However, to ease demonstration of the proposed scheme, simulations are performed for various sam- ple values of a threshold where THH and THL are assigned to same value. The mean SE values corresponding to ‘AL- FEC+LA’ are shown by dashed lines with 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Application layer SE [b/s/Hz] CDF No EC AL−FEC AL−FEC + LA; TH H = TH L = 3% AL−FEC + LA; TH H = TH L = 6% AL−FEC + LA; TH H = TH L = 9% mean; AL−FEC + LA; THH = THL = 3% mean; AL−FEC + LA; THH = THL = 6% mean; AL−FEC + LA; THH = THL = 9% Figure 2: CDF of AL spectral efficiency for ‘no EC’, ‘AL-FEC’ and ‘AL-FEC+LA’. the same color as the corresponding CDF plots. On the other hand, the correspond- ing application layer and EC PDU loss rates are shown in Figures 3 and 4, re- spectively. In cases of no LA, a fixed sam- ple MCS setting with QPSK and coding rate = 0.59 is used. The AL-FEC is as- sumed to use 20% packet redundancy for the repair packets. The EC PDU PLRs are measured over 1 second intervals, which equals the higher layer EC coding inter- val, and are accordingly reported once per second. Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 8/14
  9. 9. 10 −3 10 −2 10 −1 10 0 0.8 0.85 0.9 0.95 1 Application layer packet loss rate CDF No EC AL−FEC AL−FEC + LA; THH = THL = 3% AL−FEC + LA; TH H = TH L = 6% AL−FEC + LA; TH H = TH L = 9% Figure 3: CDF of AL packet loss rate for ‘no EC’, ‘AL-FEC’ and ‘AL-FEC+LA’. Major Observations • ‘AL-FEC’ provides better robustness as compared to ‘no EC’, i.e., with AL-FEC, the application layer packet loss rate does not exceed 1% in ap- proximately 98% of the cases and it is below 0.1% in around 97% of the cases. However, approximately 20% spectral efficiency is sacrificed due to the additional repair packets. • ‘AL-FEC+LA’ provides similar ro- bustness with improved spectral effi- ciency as compared to AL-FEC; i.e., ‘AL-FEC+LA’ that allows MCS set- ting modification at THH = THL = 3% shows that the application layer 10 −3 10 −2 10 −1 10 0 0.8 0.85 0.9 0.95 1 EC PDU loss rate CDF No EC AL−FEC AL−FEC + LA; TH H = TH L = 3% AL−FEC + LA; TH H = TH L = 6% AL−FEC + LA; TH H = TH L = 9% Figure 4: CDF of EC PDU loss rate for ‘no EC’, ‘AL-FEC’ and ‘AL-FEC+LA’. packet loss rate is lower than 1% in approximately 98% of the cases and it is below 0.1% in around 96% of the cases. Contrary to conventional AL-FEC there is no loss in spectral efficiency compared to the case with- out any AL-FEC, as the spectral ef- ficiency sacrificed for repair packets is compensated by improved adapta- tion of MCS settings. • With ‘AL-FEC+LA’ , care should be taken in the configuration of MCS modification thresholds. Configura- tion of higher values, e.g. THH = THL = 9%, could lead to lower (<95%) robustness coverage for very Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 9/14
  10. 10. low application packet loss rate tar- gets as compared to ‘AL-FEC’ even though better spectral efficiency is achieved by allowing more aggressive selection of the MCS by setting pa- rameter THH and THL to a higher value. V.B Coordination of LA and Layer 2 EC In this section, we compare the newly pro- posed mechanism of LA in coordination with 2nd layer EC scheme against two ref- erence schemes: No EC: Operation without any kind of higher layer EC scheme and Layer 2 EC: Operation with RLNC- based 2nd layer of EC in the RAN, where additional repair packets are sent only based on requests from UEs, cf. [1] for details. Figure 5 shows the CDF of application layer spectral efficiency comparing ‘no EC’, ‘2nd Layer EC’ (with no LA) and ‘2nd Layer EC+LA’. As in Section V.A we as- sumed for simplicity THH = THL . The mean SE values corresponding to ‘2nd Layer EC’ and ‘2nd Layer EC+LA’ are 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Application layer SE [b/s/Hz] CDF No EC 2nd Layer EC 2nd Layer EC + LA; TH H = TH L = 10% 2nd Layer EC + LA; TH H = TH L = 15% 2nd Layer EC + LA; THH = THL = 20% mean; 2nd Layer EC mean; 2nd Layer EC + LA; TH H = TH L = 10% mean; 2nd Layer EC + LA; TH H = TH L = 15% mean; 2nd Layer EC + LA; TH H = TH L = 20% Figure 5: CDF of AL SE for ‘no EC’, ‘2nd Layer EC’ and ‘2nd Layer EC+LA’. shown by dashed lines with the same color as the corresponding CDF plots. The corresponding performance in terms of application layer packet loss rate and EC PDU loss rate are shown in Figures 6 and 7, respectively. Configuration of mea- surements and timers is identical com- pared to that of Section V.A. To identify the optimal MCS modification threshold, further analysis of ‘2nd Layer EC+LA’ as a function of threshold THH = THL val- ues are performed and the result is shown in Figure 8. Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 10/14
  11. 11. 10 −3 10 −2 10 −1 10 0 0.8 0.85 0.9 0.95 1 Application layer packet loss rate CDF No EC 2nd Layer EC 2nd Layer EC + LA; THH = THL = 10% 2nd Layer EC + LA; TH H = TH L = 15% 2nd Layer EC + LA; TH H = TH L = 20% Figure 6: CDF of AL packet loss rate for ‘no EC’, ‘2nd Layer EC’ and ‘2nd Layer EC+LA’. Major Observations • ‘2nd layer EC’ without LA provides much higher robustness with small sacrifice on spectral efficiency as compared to ‘no EC’, i.e., ‘2nd layer EC’ shows that in >99.9% of the cases the application layer packet loss rate is kept below 0.1% at a cost of around 3% sacrifice on spectral efficiency whereas with the ’no EC’ scheme the probability of AL packet loss rates being larger than 1% is around 3%. The main reason is that with layer-2 EC, repair packets are sent only on-demand, i.e., no redun- dant repair packets as in conven- 10 −3 10 −2 10 −1 10 0 0.8 0.85 0.9 0.95 1 EC PDU loss rate CDF No EC 2nd Layer EC 2nd Layer EC + LA; TH H = TH L = 10% 2nd Layer EC + LA; TH H = TH L = 15% 2nd Layer EC + LA; TH H = TH L = 20% Figure 7: CDF of EC PDU loss rate for ‘no EC’, ‘2nd Layer EC’ and ‘2nd Layer EC+LA’. tional AL-FEC. • ‘2nd layer EC+LA’ using aggres- sive threshold values, e.g. THH = THL = 20% or 30%, can achieve even higher spectral efficiency while providing nearly 100% coverage with practically zero AL packet loss rate. VI Conclusions This white paper has proposed and eval- uated a practical mechanism of LA in co- ordination with higher layer EC schemes such as AL-FEC or layer 2 EC in the RAN. The proposed scheme targeted improving the radio network efficiency while mak- Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 11/14
  12. 12. 0 10 20 30 40 50 60 70 80 90 0.5 0.56 0.62 0.68 0.74 0.8 0.86 0.92 0.98 1.04 1.1 MeanapplicationlayerSE 0 10 20 30 40 50 60 70 80 90 0.9 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1 Threshold THH = THL Coverageat0.1%applicationlayerPLR Mean application layer SE Coverage at 0.1% application layer PLR Figure 8: Spectral efficiency and coverage of ‘2nd Layer EC+LA’ as a function of THH = THL. ing the PTM transmission reliable. The findings of the SLS-based evaluation of the proposed scheme show that the ap- plication layer user spectral efficiency is considerably improved by the proposed scheme while maintaining the required QoE in terms of application layer packet loss rates. Acknowledgement: This work was done in cooperation with Nokia Bell Labs and supported by the European Commission under the 5G-PPP project Broadcast and Multicast Communication Enablers for the Fifth-Generation of Wireless Systems 5G-XCast (H2020-ICT-2016-2 call, grant number 761498). The views expressed in this contribution are those of the au- thors and do not necessarily represent the project. References [1] F. Tesema and V. Pauli. Layer 2 FEC in 5G Broadcast / Multi- cast Networks. Nomor white pa- per, available from www.nomor.de/- resources/white-papers/, 2018. [2] Nomor Research GmbH. Real- Time Network Simulator (Re- alNeS). For more information see www.nomor.de/services/simula- tion/. [3] 3GPP. Multimedia Broadcast / Mul- ticast Service (MBMS); Protocols and Codecs (Release 15). 3GPP TS 26.346 v15.1.0, June 2018. [4] T. Stockhammer, A. Shokrollahi, M. Watson, M. Luby, and T. Ga- siba. Application Layer Forward Er- ror Correction for Mobile Multimedia Broadcasting. Handbook of Mobile Broadcasting: DVB-H, DMB, ISDB- T and Media FLO, pages 239–280, 2008. Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 12/14
  13. 13. [5] 3GPP. E-UTRA; Study on Single- Cell Point-to-Multipoint Transmis- sion for E-UTRA (Release 13). 3GPP TR 36.890, July 2015. [6] A. M. Cavalcante, E. B. Souza, J. J. Bazzo, M. J. Souza, L. Kuru, and J. Moilanen. On the System-Level Analysis of Outer Loop Link Adap- tation for IEEE 802.16e Systems. Journal of Communication and Com- puter, 2012. [7] 3GPP. 5G NR; Physical Layer Mea- surements (Release 15). 3GPP TS 38.215 v15.3.0, 2018. [8] 3GPP. 5G NR; Requirements for Support of Radio Resource Manage- ment (Release 15). 3GPP TS 38.133 v15.3.0, 2018. [9] 3GPP. 5G NR; Overall Description; Stage 2 (Release 15). 3GPP TS 38.300 v15.3.0, 2018. [10] 3GPP. 5G NR; Physical Layer Pro- cedures for Data (Release 15). 3GPP TS 38.214 v15.3.0, 2018. [11] 3GPP. 5G NR; Multiplexing and Channel Coding (Release 15). 3GPP TS 38.212 v15.2.0, June 2018. [12] ITU. Guidelines for Evaluation of Ra- dio Interface Technologies for IMT- 2020. ITU Document 5/57-E or Re- port M.2412-0, October 2017. [13] 3GPP. Technical Specification Group Radio Access Network; Study on Channel Model for Frequencies from 0.5 to 100 GHz (Rel. 14). 3GPP TR 38.901 v14.1.1, July 2017. [14] L. Yu, C. Dietrich, V. Pauli. IMT-2020 Evaluation: Calibration of NOMOR’s System Simulator. Nomor white paper, available from www.nomor.de/resources/white- papers/, November 2018. Note: This white paper is provided to you by Nomor Research GmbH. Simi- lar documents can be obtained from http://www.nomor.de. Please support our work in the social media. Consultancy Services: Please contact us in case you are interested in our services by sending an email to info@nomor.de. 3GPP related Consultancy Services: • Link- and System-Level Simulations • Research, Analyses and Concept De- velopment • Demonstration and Prototyping • 3GPP Standardization Support Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 13/14
  14. 14. • Technology Training • Patents Support Technical Areas: • Mobile Communication Networks • Mission Critical Communication • Vehicular Communication • Satellite and Broadcast • Multimedia Delivery and Content Distribution • Internet of Things Disclaimer: This paper is provided for informational purpose only. We do not accept any re- sponsibility for the content of this newslet- ter. Nomor Research GmbH has no obli- gation to update, modify or amend or to otherwise notify the reader thereof in the event that any matter stated herein, or any opinion, projection, forecast or esti- mate set forth herein, changes or subse- quently becomes inaccurate. Please note in our assessment(s) we only considered those facts known to us and therefore the results of our assessment(s) are subject to to change due to facts currently not known to us. Furthermore, please note, with respect to our assessment(s) differ- ent opinions might be expressed in the rel- evant literature and there may be some other interpretations which are scientifi- cally valid. Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000 14/14

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