Some of the key driving forces behind the transition from the UMTS based cellular system to the Long Term Evolution Advanced (LTE-A) are to improve the mean and the cell-edge throughput, improve the user fairness, and improve the quality of service (QoS) satisfaction for all users. In the latter system, relays appear as one of the most prominent enabler for improving the cell-edge user experience while increasing the system’s fairness.
In this white paper, we present the basics of relay deployments in LTE-A networks. Moreover, we analyze resource allocation problem for Relay Nodes (RN) deployments and present some of the solutions for improvement in system resource usage and QoS satisfaction. Afterwards, we introduce the capabilities of NOMOR’s LTE-A system level simulator and evaluate the performance of LTE-A relay systems under the described solutions.
Multi-layer heterogeneous network layout including small cell base stations are considered to be the key to further enhancements of the spectral efficiency achieved in mobile communication networks. It has been recognized that inter-cell interference has become the limiting factor when trying to achieve not only high average user satisfaction, but a high degree of satisfaction for as many users as possible. Therefore, inter-cell interference coordination (ICIC) lies in the focus of researchers defining next generation mobile communication standards, such as LTE-A.
Building upon [1], this paper provides an overview over the background calling for ICIC in heterogeneous LTE-A networks. It outlines techniques standardized in Rel. 10 of LTE-A, discusses them showing their benefits and limitations by means of system-level simulations and motivates the importance of self optimizing network (SON) procedures for ICIC in LTE-A.
Heterogeneous LTE Networks and Inter-Cell Interference Coordination - Dec 201...Eiko Seidel
Initial deployments of LTE networks are based on so-called homogeneous networks consisting of base stations providing basic coverage, called macro base stations. The concept of heterogeneous networks has recently attracted considerable attention to optimize performance particularly for unequal user or traffic distribution. Here, the layer of planned high-power macro eNBs is overlaid with layers of lower-power pico or femto eNBs that are deployed in a less well planed or even entirely uncoordinated manner. Such deployments can achieve significantly improved overall capacity and cell-edge performance and are often seen as the second phase in LTE network deployment.
This paper discusses the concept of heterogeneous networks as compared to homogeneous networks. It demonstrates the need for inter-cell interference coordination (ICIC) and outlines some ICIC methods that are feasible with release 8 /9 of the LTE standard. System-level simulation results illustrate the benefits of the various features discussed in the following.
Final Performance Evaluation of 3GPP NR eMBB within 5G-PPP consortiumEiko Seidel
Nomor Research contributed extensive system level simulation results to the evaluation group of the 5G-PPP consortium as an independent source. The evaluation has been submitted to 34th meeting of the ITU-R Working Party 5D confirming that the 5G requirements of 3GPP New Radio air interface are indeed fulfilled. With the presentation of the evaluation reports at the ITU-R Working Party 5D meeting held in Geneva, Switzerland, in February 2020, the independent evaluation activity has officially been closed.
The system level simulations performed by Nomor Research GmbH are only a part of the overall evaluation of the 5G NR air interface. A summary of the simulation-based evaluation based on the 5G NR RealNeS system simulator is being provided in this white paper.
Evaluation of 5G Data Duplication for URLLC - Nomor Reseach GmbHEiko Seidel
As you might know Data Duplication can be used in combination of Carrier Aggregation or Dual Connectivity to increase reliability for services such as URLLC. Enclosed a paper of my colleague Dr. Volker Pauli with 5G system/protocol level simulation results for different scenarios for a CU/DU split architecture. Packet loss rates of 10-5 are feasible for URLLC within restricted service areas.
5G RAN - Split of Functions between Central and Distributed UnitEiko Seidel
R3-161285 from 3GPP TSG RAN WG3 Meeting #92 in Nanjing, China, 23 - 27 May 2016
Source: Deutsche Telekom, Orange, T-Mobile US, Telstra, SK Telecom
See: www.3gpp.org
The document shares some practical considerations from an operator viewpoint with the aim to aid the discussions to find reasonable functional split options between central and distributed unit for the NR.
Towards achieving-high-performance-in-5g-mobile-packet-cores-user-plane-functionEiko Seidel
White Paper Intel SK Telekom
This paper presents the architecture for a user plane function (UPF) in the mobile packet core (MPC) targeting 5G deployments.
Multi-layer heterogeneous network layout including small cell base stations are considered to be the key to further enhancements of the spectral efficiency achieved in mobile communication networks. It has been recognized that inter-cell interference has become the limiting factor when trying to achieve not only high average user satisfaction, but a high degree of satisfaction for as many users as possible. Therefore, inter-cell interference coordination (ICIC) lies in the focus of researchers defining next generation mobile communication standards, such as LTE-A.
Building upon [1], this paper provides an overview over the background calling for ICIC in heterogeneous LTE-A networks. It outlines techniques standardized in Rel. 10 of LTE-A, discusses them showing their benefits and limitations by means of system-level simulations and motivates the importance of self optimizing network (SON) procedures for ICIC in LTE-A.
Heterogeneous LTE Networks and Inter-Cell Interference Coordination - Dec 201...Eiko Seidel
Initial deployments of LTE networks are based on so-called homogeneous networks consisting of base stations providing basic coverage, called macro base stations. The concept of heterogeneous networks has recently attracted considerable attention to optimize performance particularly for unequal user or traffic distribution. Here, the layer of planned high-power macro eNBs is overlaid with layers of lower-power pico or femto eNBs that are deployed in a less well planed or even entirely uncoordinated manner. Such deployments can achieve significantly improved overall capacity and cell-edge performance and are often seen as the second phase in LTE network deployment.
This paper discusses the concept of heterogeneous networks as compared to homogeneous networks. It demonstrates the need for inter-cell interference coordination (ICIC) and outlines some ICIC methods that are feasible with release 8 /9 of the LTE standard. System-level simulation results illustrate the benefits of the various features discussed in the following.
Final Performance Evaluation of 3GPP NR eMBB within 5G-PPP consortiumEiko Seidel
Nomor Research contributed extensive system level simulation results to the evaluation group of the 5G-PPP consortium as an independent source. The evaluation has been submitted to 34th meeting of the ITU-R Working Party 5D confirming that the 5G requirements of 3GPP New Radio air interface are indeed fulfilled. With the presentation of the evaluation reports at the ITU-R Working Party 5D meeting held in Geneva, Switzerland, in February 2020, the independent evaluation activity has officially been closed.
The system level simulations performed by Nomor Research GmbH are only a part of the overall evaluation of the 5G NR air interface. A summary of the simulation-based evaluation based on the 5G NR RealNeS system simulator is being provided in this white paper.
Evaluation of 5G Data Duplication for URLLC - Nomor Reseach GmbHEiko Seidel
As you might know Data Duplication can be used in combination of Carrier Aggregation or Dual Connectivity to increase reliability for services such as URLLC. Enclosed a paper of my colleague Dr. Volker Pauli with 5G system/protocol level simulation results for different scenarios for a CU/DU split architecture. Packet loss rates of 10-5 are feasible for URLLC within restricted service areas.
5G RAN - Split of Functions between Central and Distributed UnitEiko Seidel
R3-161285 from 3GPP TSG RAN WG3 Meeting #92 in Nanjing, China, 23 - 27 May 2016
Source: Deutsche Telekom, Orange, T-Mobile US, Telstra, SK Telecom
See: www.3gpp.org
The document shares some practical considerations from an operator viewpoint with the aim to aid the discussions to find reasonable functional split options between central and distributed unit for the NR.
Towards achieving-high-performance-in-5g-mobile-packet-cores-user-plane-functionEiko Seidel
White Paper Intel SK Telekom
This paper presents the architecture for a user plane function (UPF) in the mobile packet core (MPC) targeting 5G deployments.
Abstract— Scheduler is the backbone of intelligence in a LTE network. Scheduler will often have clashing needs that can make its design very complex and non-trivial.
The overall system throughput needs to be maintained at the best possible value without sacrificing the cell edge user experience.
In this paper, authors compared different scheduler designs for voice and packet services. They explained the role of configuration parameters through simulations. These parameters control the tradeoff between the sector throughput and the fairness in system through. They explained a possible scheduler implementation.
The need for Synchronisation in Telecommunications3G4G
The need for some sort of synchronisation in telecommunications has existed almost as long as telecommunications itself. However synchronisation in the form dominant in the last 50 or so years arose from the introduction of Pulse Code Modulation (PCM) for transmission of voice telephony, and the use of digital switching techniques to establish voice circuits between subscribers as required. Martin Kingston explains.
*** Shared with Permission - ITP Journal Volume 10 | Part 1 - 2016 ***
Sample-by-sample and block-adaptive robust constant modulus-based algorithmsDr. Ayman Elnashar, PhD
In this study, a robust sample-by-sample linearly constrained constant modulus algorithm (LCCMA) and a robust adaptive block-Shanno constant modulus algorithm (BSCMA) are developed. The well-established quadratic inequality constraint approach is exploited to add robustness to the developed algorithms. The LCCMA algorithm is implemented using a fast steepest descent adaptive algorithm, whereas the BSCMA algorithm is realised using a modified Newton’s algorithm without the inverse of Hessian matrix estimation. The developed algorithms are exercised to cancel the multiple access interference in a loaded direct sequence code division multiple access (DS/CDMA) system. Simulations are presented in a rich multipath environment with a severe near-far effect to evaluate the robustness of the proposed DS/CDMA detectors. Finally, a comprehensive comparative analysis between the sample-by-sample and block-adaptive constant modulus-based detectors is presented. It has been demonstrated that the developed robust BSCMA detector offers rapid convergence speed and very low computational complexity, whereas the developed robust LCCMA detector engenders about 5 dB improvement in the output signal-to-interference-plus-noise ratio over the BSCMA detector.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
LTE networks get more mature and new terminals of different capabilities are being introduced. 3GPP just defined the new LTE-A UE categories to support terminals with peak data rates of up to 450 Mbps in the downlink. This white paper provides an overview of all existing LTE/LTE-A UE categories and presents the new Release 11 capabilities that have just been standardized. Furthermore it describes key scenarios and use cases such as the support for downlink carrier aggregation with 3 downlink carriers with up to 60 MHz of total bandwidth.
LTE-Advanced standardisation in Release 10 was completed some time ago and vendors are busy implementing the latest features. In a previous 3GPP newsletter we introduced the various Release 11 work and study items. By now Release 11 is well advanced and first features will be completed at the next RAN plenary in September 2012.
This newsletter provides an overview about Release 11 enhancements defined for one of most important LTE-Advanced features – Carrier Aggregation. Core of the described enhancements are the support of Carrier Aggregation in Heterogeneous Networks with non collocated cell sites.
Topics covered in this presentation:
1. RF spectrum and GSM specifications
2. FDMA and TDMA
3. Digital Voice Transmission
4. Channel coding, Interleaving and Burst formatting
5. GMSK
6. Frame structure of GSM
7. Corrective actions against multipath fading
This is presentation by Keysight technologies on 5G NR Dynamic Spectrum Sharing. Very well articulated presentation as always by Keysight. Details on the 3GPP support for NR DSS implementation in LTE bands in Rel 15 and Rel 16.
Simulation and Performance Analysis of Long Term Evolution (LTE) Cellular Net...ijsrd.com
In the development, standardization and implementation of LTE Networks based on Orthogonal Freq. Division Multiple Access (OFDMA), simulations are necessary to test as well as optimize algorithms and procedures before real time establishment. This can be done by both Physical Layer (Link-Level) and Network (System-Level) context. This paper proposes Network Simulator 3 (NS-3) which is capable of evaluating the performance of the Downlink Shared Channel of LTE networks and comparing it with available MatLab based LTE System Level Simulator performance.
Mpls tp as packet platform for critical services in power transmissionHughCab
Beyond the trend of using IP as the “up to date technology” for SCADA (IEC
60870-5-104) and protections scheme integrated to a centralized management
of the load (Sinchrophasors PMU), there is the need to approach the automatic
switching and intrinsic autonomy of routing algorithms to provide smart
capability to the communications network [1]. For long time IP equipment
manufacturers have been trying to penetrate the electrical utilities with partial
success, they were able to support only added value services as IP Video, VoIP
and corporate IP traffic which is are not “critical” or essential to the electrical
power system operation.
On this paper is presented a theoretical-practical evaluation of the MPLS-TP
protocol which offers an IP platform according to the complimentary services
requirements (high bandwidth) as well for reliable channels features through
the emulation of TDM systems with delay, symmetry and self-healing switching
in order to warrant the correct operation of critical services as Teleprotection,
Differential Relays and Sinchrophasors.
Key time measurements will be presented which certifies the theoretical
reliability of MPLS-TP as main IP communication platform in electrical
transmission systems.
One of the main challenges faced by the developing (3GPP-LTE-Advanced) standard is providing high throughput at the cell edge.
One solution to improve coverage is the use of fixed relays.
Abstract— Scheduler is the backbone of intelligence in a LTE network. Scheduler will often have clashing needs that can make its design very complex and non-trivial.
The overall system throughput needs to be maintained at the best possible value without sacrificing the cell edge user experience.
In this paper, authors compared different scheduler designs for voice and packet services. They explained the role of configuration parameters through simulations. These parameters control the tradeoff between the sector throughput and the fairness in system through. They explained a possible scheduler implementation.
The need for Synchronisation in Telecommunications3G4G
The need for some sort of synchronisation in telecommunications has existed almost as long as telecommunications itself. However synchronisation in the form dominant in the last 50 or so years arose from the introduction of Pulse Code Modulation (PCM) for transmission of voice telephony, and the use of digital switching techniques to establish voice circuits between subscribers as required. Martin Kingston explains.
*** Shared with Permission - ITP Journal Volume 10 | Part 1 - 2016 ***
Sample-by-sample and block-adaptive robust constant modulus-based algorithmsDr. Ayman Elnashar, PhD
In this study, a robust sample-by-sample linearly constrained constant modulus algorithm (LCCMA) and a robust adaptive block-Shanno constant modulus algorithm (BSCMA) are developed. The well-established quadratic inequality constraint approach is exploited to add robustness to the developed algorithms. The LCCMA algorithm is implemented using a fast steepest descent adaptive algorithm, whereas the BSCMA algorithm is realised using a modified Newton’s algorithm without the inverse of Hessian matrix estimation. The developed algorithms are exercised to cancel the multiple access interference in a loaded direct sequence code division multiple access (DS/CDMA) system. Simulations are presented in a rich multipath environment with a severe near-far effect to evaluate the robustness of the proposed DS/CDMA detectors. Finally, a comprehensive comparative analysis between the sample-by-sample and block-adaptive constant modulus-based detectors is presented. It has been demonstrated that the developed robust BSCMA detector offers rapid convergence speed and very low computational complexity, whereas the developed robust LCCMA detector engenders about 5 dB improvement in the output signal-to-interference-plus-noise ratio over the BSCMA detector.
Duplexing mode, ARB and modulation approaches parameters affection on LTE upl...IJECEIAES
The next generation of radio technologies designed to increase the capacity and speed of mobile networks. LTE is the first technology designed explicitly for the Next Generation Network NGN and is set to become the de-facto NGN mobile access network standard. It takes advantage of the NGN's capabilities to provide an always-on mobile data experience comparable to wired networks. In this paper LTE uplink waveforms displayed with various duplexing mode, Allocated Resources Blocks ARB, Modulation types and total information per frame, QPSK and 16 QAM used as modulation techniques and tested under AWGN and Rayleigh channels, similarity and interference of the generated waveforms tested using auto-correlation and cross-correlation respectively.
LTE networks get more mature and new terminals of different capabilities are being introduced. 3GPP just defined the new LTE-A UE categories to support terminals with peak data rates of up to 450 Mbps in the downlink. This white paper provides an overview of all existing LTE/LTE-A UE categories and presents the new Release 11 capabilities that have just been standardized. Furthermore it describes key scenarios and use cases such as the support for downlink carrier aggregation with 3 downlink carriers with up to 60 MHz of total bandwidth.
LTE-Advanced standardisation in Release 10 was completed some time ago and vendors are busy implementing the latest features. In a previous 3GPP newsletter we introduced the various Release 11 work and study items. By now Release 11 is well advanced and first features will be completed at the next RAN plenary in September 2012.
This newsletter provides an overview about Release 11 enhancements defined for one of most important LTE-Advanced features – Carrier Aggregation. Core of the described enhancements are the support of Carrier Aggregation in Heterogeneous Networks with non collocated cell sites.
Topics covered in this presentation:
1. RF spectrum and GSM specifications
2. FDMA and TDMA
3. Digital Voice Transmission
4. Channel coding, Interleaving and Burst formatting
5. GMSK
6. Frame structure of GSM
7. Corrective actions against multipath fading
This is presentation by Keysight technologies on 5G NR Dynamic Spectrum Sharing. Very well articulated presentation as always by Keysight. Details on the 3GPP support for NR DSS implementation in LTE bands in Rel 15 and Rel 16.
Simulation and Performance Analysis of Long Term Evolution (LTE) Cellular Net...ijsrd.com
In the development, standardization and implementation of LTE Networks based on Orthogonal Freq. Division Multiple Access (OFDMA), simulations are necessary to test as well as optimize algorithms and procedures before real time establishment. This can be done by both Physical Layer (Link-Level) and Network (System-Level) context. This paper proposes Network Simulator 3 (NS-3) which is capable of evaluating the performance of the Downlink Shared Channel of LTE networks and comparing it with available MatLab based LTE System Level Simulator performance.
Mpls tp as packet platform for critical services in power transmissionHughCab
Beyond the trend of using IP as the “up to date technology” for SCADA (IEC
60870-5-104) and protections scheme integrated to a centralized management
of the load (Sinchrophasors PMU), there is the need to approach the automatic
switching and intrinsic autonomy of routing algorithms to provide smart
capability to the communications network [1]. For long time IP equipment
manufacturers have been trying to penetrate the electrical utilities with partial
success, they were able to support only added value services as IP Video, VoIP
and corporate IP traffic which is are not “critical” or essential to the electrical
power system operation.
On this paper is presented a theoretical-practical evaluation of the MPLS-TP
protocol which offers an IP platform according to the complimentary services
requirements (high bandwidth) as well for reliable channels features through
the emulation of TDM systems with delay, symmetry and self-healing switching
in order to warrant the correct operation of critical services as Teleprotection,
Differential Relays and Sinchrophasors.
Key time measurements will be presented which certifies the theoretical
reliability of MPLS-TP as main IP communication platform in electrical
transmission systems.
One of the main challenges faced by the developing (3GPP-LTE-Advanced) standard is providing high throughput at the cell edge.
One solution to improve coverage is the use of fixed relays.
Is Social Media Marketing truth or hype? See this study by the people at Heat, conducted in March 2012.
Find out how ad/marketing people use and percieve social media compared to "normal people". Oh, and the last part , Office Holiday Parties, is a must read. And I thought the Mad Men days were over.
Similar to Relay Enhanced LTE-Advanced Networks – Resource Allocation and QoS provisioning - Jul 2012, Eiko Seidel, Chief Technical Officer, Nomor Research
Joint Interference Coordination and Spatial Resource ReuseIJMTST Journal
Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. Deploying relay nodes is foreseen a cost-efficient solution to combat the severe propagation loss at cell edge. However, relay cell coverage is limited by the low transmit power, limited antenna capabilities and wireless backhaul link bottleneck which may lead to load imbalances and hence low resource utilization efficiency. Further challenges in relay deployments are attributed to increased interference levels in the network compared with macro cell-only deployments, causing degradation of the user throughput. In this context, relay cell coverage expansion and interference coordination techniques are expected to improve the performance of relay deployments. In this study, we analyze the impact of the additional interference due to the relay node transmissions. Jointly with our previous study on cell expansion, spatial resource reuse from the graph-theoretical perspective. Next, our focus shifts to developing a simple but efficient radio resource management algorithm which enables the spatial resource reuse, the pricing- based radio resource management (PRRM) strategy. The PRRM performs spatial reuse for interference-free users operating in the high signal-to-interference-and-noise ratio (SINR) region, while guaranteeing the signal quality of interference-susceptible users usually located near the coverage boundary. By applying the PRRM, we evaluate the potential benefits of the spatial resource reuse.
What is the purpose of 5G flexible duplexing?
The purpose of 5G flexible duplexing is to allow the most flexible use of an operator's spectrum for time-frequency resources in a single framework. 5G Flexible duplexing should inherently support both paired and unpaired spectrum and be forward compatible with full-duplex 5G.
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.
Survey on scheduling and radio resources allocation in lteijngnjournal
This paper focuses on an essential task of the enhanced NodeB eNodeB element in LTE architecture, the
Radio Resource Manager RRM, which aims to accept or reject requests for connection to the network
based on some constraints and ensuring optimal distribution of radio resources between Users Equipments
UEs. Its main functionalities include Admission Control AC and Packet Scheduling PS.
This paper will center mainly on the PS part of the RRM task, which performs the radio resource
allocation in both uplink and downlink directions. Several approaches and algorithms have been proposed
in the literature to address this need (allocate resources efficiently), the diversity and multitude of
algorithms is related to the factors considered for the optimal management of radio resource, specifically,
the traffic type and the QoS (Quality of Service) requested by the UE.
In this article, an art’s state of the radio resource allocation strategies and a detailed study of several
scheduling algorithms proposed for LTE (uplink and downlink) are made. Therefore, we offer our
evaluation and criticism.
Distributed Utility-Based Energy Efficient Cooperative Medium Access Control...IJMER
Cooperative communication, that utilizes near terminals to relay the overhearing
information to grasp the variability gains, choices a nice potential to strengthen the transmission
potency in wireless networks. to the subsume the hard medium access interactions evoked by relaying
and leverage the advantages of such cooperation, associate economical Cooperative Medium Access
management (CMAC) protocol is required. throughout this paper, we've got an inclination to tend to
propose a completely unique cross-layer Wide unfold Energy-adaptive Location-based CMAC
protocol, notably WEAL-CMAC, for Mobile Ad-hoc Networks (MANETs). the design objective of
WEAL-CMAC is to strengthen the performance of the MANETs in terms of network amount and
energy potency. a wise energy consumption model is used throughout this paper, that takes the energy
consumption on each transceiver instrumentation and transmit instrumentation into thought. A
distributed utility-based best relay different strategy is incorporated, that selects the most effective
relay supported location information and residual energy. moreover, with the aim of enhancing the
spacial apply, associate innovative network allocation vector setting is provided to the subsume the
variable transmission power of the beginning and relay terminals. we've got an inclination to tend to
point that the planned WEAL-CMAC considerably prolongs the network amount below varied
circumstances even for prime instrumentation energy consumption cases by comprehensive simulation
study
Spectrum Sharing between Cellular and Wi-Fi Networks based on Deep Reinforcem...IJCNCJournal
Recently, mobile traffic is growing rapidly and spectrum resources are becoming scarce in wireless networks. Due to this, the wireless network capacity will not meet the traffic demand. To address this problem, using cellular systems in an unlicensed spectrum emerged as an effective solution. In this case, cellular systems need to coexist with Wi-Fi and other systems. For that, we propose an efficient channel assignment method for Wi-Fi AP and cellular NB, based on the DRL method. To train the DDQN model, we implement an emulator as an environment for spectrum sharing in densely deployed NB and APs in wireless heterogeneous networks. Our proposed DDQN algorithm improves the average throughput from 25.5% to 48.7% in different user arrival rates compared to the conventional method. We evaluated the generalization performance of the trained agent, to confirm channel allocation efficiency in terms of average throughput under the different user arrival rates.
Spectrum Sharing between Cellular and Wi-Fi Networks based on Deep Reinforcem...IJCNCJournal
Recently, mobile traf ic is growing rapidly and spectrum resources are becoming scarce in wireless
networks. Due to this, the wireless network capacity will not meet the traf ic demand. To address this
problem, using cellular systems in an unlicensed spectrum emerged as an ef ective solution. In this case,
cellular systems need to coexist with Wi-Fi and other systems. For that, we propose an ef icient channel
assignment method for Wi-Fi AP and cellular NB, based on the DRL method. To train the DDQN model,
we implement an emulator as an environment for spectrum sharing in densely deployed NB and APs in
wireless heterogeneous networks. Our proposed DDQN algorithm improves the average throughput from
25.5% to 48.7% in dif erent user arrival rates compared to the conventional method. We evaluated the
generalization performance of the trained agent, to confirm channel allocation ef iciency in terms of
average throughput under the dif erent user arrival rates
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize
the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and
time dimension. So several scheduling algorithms need to be analyzed for femtocells networks.
In this paper we introduce a performance analysis of three distinct scheduling algorithms of
mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in
terms of throughput, packet loss ratio, fairness index and spectral efficiency.
PERFORMANCE ANALYSIS OF RESOURCE SCHEDULING IN LTE FEMTOCELLS NETWORKScscpconf
3GPP has introduced LTE Femtocells to manipulate the traffic for indoor users and to minimize the charge on the Macro cells. A key mechanism in the LTE traffic handling is the packet
scheduler which is in charge of allocating resources to active flows in both the frequency and time dimension. So several scheduling algorithms need to be analyzed for femtocells networks. In this paper we introduce a performance analysis of three distinct scheduling algorithms of mixed type of traffic flows in LTE femtocells networks. The particularly study is evaluated in terms of throughput, packet loss ratio, fairness index and spectral efficiency.
ADAPTIVE HANDOVER HYSTERESIS AND CALL ADMISSION CONTROL FOR MOBILE RELAY NODESIJCNCJournal
The aim of equipping a wireless network with a mobile relay node is to support broadband wireless communications for vehicular users and their devices. The high mobility of vehicular users, possibly at a very high velocity in the area in which two cells overlap, could cause the network to suffer from a reduced handover success rate and, hence, increased radio link failure. The combined impact of these problems is service interruptions to vehicular users. Thus, the handover schemes are crucial in solving these problems. In this work, we first present the adaptive handover hysteresis scheme for the wireless network with mobile relay nodes in the high-speed train scenario. Specifically, our proposed adaptive hysteresis scheme is based on the velocity of the train. Second, the handover call dropping probability is reduced by introducing a modified call admission control scheme to support radio resource reservation for handover calls that prioritizes handover calls of mobile relay over the other calls. The proposed solution in which adaptive parameter is combined with call admission control is evaluated by system level simulation. Our simulation results illustrate an increased handover success rate and reduced radio link failures.
LTE QOS DYNAMIC RESOURCE BLOCK ALLOCATION WITH POWER SOURCE LIMITATION AND QU...IJCNCJournal
3GPP has defined the long term evolution (LTE) for 3G radio access in order to maintain the future
competitiveness for 3G technology, the system provides the capability of supporting a mixture of services
with different quality of service (QoS) requirements. This paper proposes a new cross-layer scheduling
algorithm to satisfy better QoS parameters for real time applications. The proposed algorithm takes care of
allocating resource blocks (RBs) with different modulation and coding schemes (MCS) according to target
bit error rate (BER), user equipment supportable MCS, queue stability constraints and available transmit
power constraints. The proposed algorithm has been valued, compared with an earlier allocation algorithm
in terms of service rate and packet delay and showed better performance regards the real time
applications.
The 3GPP Long Term Evolution Advanced (LTE-A) standard specifies a set of pioneer features such as relay nodes and carrier aggregation. At the same time, the Software Defined Networks (SDN) have become an emerging technology which provides centralized control and programmability to modern networks. In the current communication environment, cloud computing could combine the advantages of both technologies in order to create a novel cloud assisted Software Defined LTEA architecture with relay nodes. Moreover, due to the increased requirements of modern services, the optimal resource allocation is a necessity. In such a context, this paper describes a QoS aware cross carrier scheduler for downlink flows, aiming at the optimization of system resources allocation. The proposed scheduler is evaluated against the PF, MLWDF, EXP/PF, EXP RULE, LOG RULE, FLS and FLSA schedulers in a cloud assisted Software Defined LTE-A topology with relay nodes. Simulation results show that the proposed scheduler improves the real time services performance while at the same time maintains an acceptable performance for best effort flows.
Mobiles Energy Consumption in LTE Uplink Networksidescitation
3GPP has standardized different multicarrier access methods in the downlink
and uplink for LTE. While Orthogonal Frequency Division Multiple Access (OFDMA) is
chosen in the downlink, Single Carrier Frequency Division Multiple Access (SC-FDMA) is
chosen in the uplink due to its low Peak-to-Average Power Ratio (PAPR) which plays a
crucial role in the User Equipment’s (UE) power consumption. This paper presents two set
of analysis- first being the performance and comparison of Best-Effort Resource Block (RB)
Scheduling algorithms based on the Resource Block usage ratio and their impact on the
overall throughput. The second is to determine the Signal-to-Interference-plus-Noise Ratio
(SINR) per RB per UE. As the SINR at any instant is directly proportional to the power of
the UE/RB, under this assumption the UE/RB power can be reduced. Based on the
minimum SINR/UE/RB that can be achieved, the power control is then introduced on each
of the UE/RB to obtain the least possible power for transmitting the data while maintaining
the throughput. A Channel Quality Indicator (CQI) table is used as a reference to obtain the
new SINR for each UE/RB. The difference between the new and the old SINR is calculated
which gives the amount by which the UE/RB power can be reduced without affecting the
throughput. The results obtained show a reduction in the power consumption by upto 28%.
Cross layer design for power control and linkIJCNCJournal
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Relay Enhanced LTE-Advanced Networks – Resource Allocation and QoS provisioning - Jul 2012, Eiko Seidel, Chief Technical Officer, Nomor Research
1. Relay Enhanced LTE-Advanced
Networks – Resource Allocation
and QoS provisioning
Thiago M. de Moraes, Muhammad Danish Nisar,
Eiko Seidel,
NOMOR Research GmbH, Munich, Germany
July, 2012
Summary
Some of the key driving forces behind the
transition from the UMTS based cellular system
to the Long Term Evolution Advanced (LTE-A)
are to improve the mean and the cell-edge
throughput, improve the user fairness, and
improve the quality of service (QoS) satisfaction
for all users. In the latter system, relays appear
as one of the most prominent enabler for
improving the cell-edge user experience while
increasing the system’s fairness.
In this white paper, we present the basics of
relay deployments in LTE-A networks. Moreover,
we analyze resource allocation problem for Relay
Nodes (RN) deployments and present some of
the solutions for improvement in system
resource usage and QoS satisfaction. Afterwards,
we introduce the capabilities of NOMOR’s LTE-A
system level simulator and evaluate the
performance of LTE-A relay systems under the
described solutions.
Introduction & Motivation
During the past few years mobile operators have
experienced an increase in the data rate demand
mainly due to the popularization of the
smartphones and their data hungry applications.
In order to maintain the competitiveness of their
system and to be able to support high data rate
demands, the 3rd Generation Partnership project
(3GPP) has proposed LTE as a possible
candidate technology for future mobile networks.
However, as the achieved rate was still under
the ITU requirement for the 4th generation of
mobile services [1][2], new features were added
to develop the so called LTE Advanced standard.
Advanced relaying is one of the most prominent
features in LTE-A systems, targeting at
improvement of the cell-edge user performance
and fairness among users. Relays, in LTE-A, are
designed to be low cost and lower power nodes
which can be easily and quickly deployed when
needed. In its release 10, LTE-A has
standardized the use of the so-called type-1
relays which are non-transparent relays: when
the RN is active it is seen by the eNB as a User
Equipment (UE), whereas the UEs close to the
RN coverage see it as a regular eNB, i.e., the RN
terminates all the layer-2 and layer-3 radio
interfaces. Therefore, the relay is supposed to
maintain its own physical cell id and to broadcast
all control and reference signalling to the
subordinate UEs. Moreover, the scheduling for
the Relay-attached UE (R-UEs) is done in the RN,
independently of the eNB scheduler.
The most challenging feature in a Relay
Enhanced Network (REN) is the management of
wireless backhaul link. Differently from a regular
eNB and from other access technologies, the
relay node does not have a wired connection to
the EPC, or the core network. In this case
wireless backhaul link is established between the
RN and the eNB during the RN connection
Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000
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2. phase. From this moment onwards, the latter
acts as a proxy server towards the core network
and is called Donor eNB (DeNB) due to the fact
that this one donates its radio resources to the
RN’s backhaul link. According to the way that the
wireless backhaul link is allocated, the RNs can
be classified as:
In-band, when the backhaul link is allocated on
the same carriers as the access link
Out-band, when the backhaul link and the
access link are allocated on different carries.
f1
f1
f1
f1
f1
(f2)
f2
Figure 1: In-band (top) and out-band (bottom)
modes of relay operation
For in-band relays, as both access and the
backhaul links use the same carrier further
constraints have to be imposed to avoid self
interference on the relay antennas. In LTE-A, the
links are time multiplexed with the help of
MBSFN sub-frames. These are special subframes initially introduced for multimedia
broadcasting during which the UEs will only
receive if they are engaged in the broadcast
service. In an enhanced realy scenario, they are
used to inform the subordinate UEs of a RN that
no transmission is expected in the downlink
during that sub-frame. In this case, UE would
automatically turn off the receiver to save
battery. The uplink case is easier, since the RN
may choose not to schedule any data from UEs
for the sub-frames during which it will transmit
to the DeNB. However, it is important to note
that according to the standard, it is not possible
to use MBSFN sub-frames at certain locations in
the frame structure, since there are broadcast
messages,
synchronization
signals,
and
information blocks that the UE has to recieve.
Therefore some sub-frames cannot be used as
an MBSFN sub-frames.
This time segregation is one of the greatest
challenges when scheduling resources for inband RNs at the DeNB because the data can only
be sent inside a limited number of MBSFN subframes.
In the out-band relay case, the isolation between
backhaul and access links is already achieved by
definition in the frequency domain. Thus, no
time constraint is imposed to the backhaul link
scheduling. Nevertheless, from an operator
point-of-view the allocation of a separate carrier
for RN access link might not always be possible
due to limited spectrum or high cost involved in
spectrum licensing and to the inefficiency in
allocating R-UEs only in this frequency band.
Fortunately, LTE-A also standardized the usage
of Carrier Aggregation (CA). CA is one of the
major innovations targeting the enhancement of
the peak performance in LTE-A. It consists of
enabling the user’s service in up to five carriers
simultaneously. A single carrier is used as the
Primary Component Carrier (PCC) which is
always active and is responsible to carry out all
the control procedures. Whereas the other
carriers, the so-called Secondary Component
Carriers (SCCs), are activated on demand to
increase the UE’s performance.
Figure 2: Carrier aggregation for out-band relay
deployments.
It turns out that carrier aggregation offers an
attractive solution for out-band relay deployment
by allowing the carrier used for the backhaul link
to be reused by the direct link at the DeNB. In
Nomor Research GmbH / info@nomor.de / www.nomor.de / T +49 89 9789 8000
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3. Figure 2, we show a scenario where two
component carriers (CC) are configured. While
the macro-attached user equipments (M-UEs)
have their maximum achievable capacity
enhanced by the introduction of a SCC, the RUEs and the RNs use distinct CCs as their PCC.
As we have already mentioned, the scheduling,
in a LTE-A REN, is done in a distributed fashion.
However, the DeNB has to provide enough data
to the relay node such that the system fairness
and possible QoS requirements are maintained.
Hence, in parallel to the M-UEs resource
allocation, other issues must also be considered
in the design of a relaying system:
Number of MBSFN frames to be placed in each
radio frame for the in-band relays.
Resource partitioning between backhaul and
access link.
Multiplexing of bearers with possibly different
QCIs in each backhaul portion at the DeNB.
For delay-constrained bearers: split of delay
budget between backhaul and access link.
In the remainder of this paper we will give an
insight on the above issues.
Resource Partitioning Principles
A simple resource allocation strategy is to
partition the resources at the DeNB by
considering the number of macro users and relay
attached users to estimate the fraction of
resources that can be assigned to the backhaul
link: the fair share of resources for the backhaul
link is given as:
ε =
NR
⋅δ ,
NR + NM
where NR is the number of relay-attached UEs in
the above equation, while NM is the number of
macro UEs which are always served directly by
the DeNB. δ is a factor that scales ε depending
on the total number of resources available:
For in-band relay case, [3][4], given a certain
fixed number P of MBSFN frames in a period of
NF consecutive sub-frames
N
δ = F.
P
For the out-band relay, [4][5], δ is the ratio
between number of carriers that can transport
the backhaul link and the total number of
carries used at the DeNB.
A second resource partition algorithm is the so
called Fair-Throughput (Fair-TP) strategy which
allows for dynamic partitioning: For a fixed
number of MBSFN sub-frames, the algorithm
computes the aggregate average throughput
Φ on the backhaul link and Φ on the access
B
M
link to all macro UEs. Within the non-MBSFN
frames it is expected that Φ increases, while
M
the macro users are scheduled, and that
Φ decreases. The idea behind this strategy is
B
to allocate resource to the backhaul link until
NR
ΦB
<
NM
ΦM
,
i.e., as long as the backhaul link is lagging
behind we allocate resources to the RN, and only
when the above condition is satisfied the macro
UEs are allocated.
While in in-band relay scenarios the prioritization
of the backhaul link is reasonable due to the few
transmission opportunities, this approach might
not be required when using out-band RNs due to
the carrier separation. Hence, in this scenario the
resource allocation can be simplified by including
the backhaul link in the regular Proportional-Fair
scheduling process, the so-called ExtPropFair
strategy. In this case, the RN is viewed as a
super user from the perspective of the
scheduler. In order to account for the fact that
all the subordinate R-UEs are multiplexed into
their serving RN backhaul link the usual PropFair metric is scaled with the number of attached
R-UEs.
From the presented strategies, we can notice
that although the Fair-RU strategy is simple and
low complexity algorithm it does not consider the
channel state of the backhaul link and might lead
to under or overcompensation of the backhaul
link. Thus, the Fair-TP has the advantage of
partially considering the channel conditions. The
obvious advantages of ExtPropFair are less
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4. complexity and simple integration of backhaul
and access link quality in the overall decision
process.
QoS-aware Scheduling for Relay Enhanced
Networks
The introduction of the second hop in a relay
enhanced network (REN) introduces new
challenges for the support of QoS-aware
services. In such networks, resource allocation
on the downlink direction for the R-UEs is
performed in two stages: In the first stage, while
serving the macro eNB-attached UEs (M-UEs),
the DeNB transfers the user data to the RN by
allocating resources to the RN backhaul link.
Afterwards, each RN schedules the previously
received data to their subordinates R-UEs. In
other words, a packet destined to a R-UE has to
undergo two scheduling processes. In order to
ensure that all QoS requirements hold across
both radio links, we must have
TDeNB − RN + TRN −UE ≤ DPr ofile
B UE
≥ GBRQoS
T DeNB − RN + T RN −UE
where TDeNB-RN is time between the arrival of the
packet at the DeNB until it is received at the RN,
TRN-UE is the interval between the packet
reception in the RN and the time the packet is
received at the R-UE, and DProfile is the delay
requirement of the corresponding flow.
Moreover, BUE is the volume of data transferred
in the time interval TDeNB-UE+TRN-UE and GBRQoS is
the rate requirement of the used QoS profile.
To this end the schedulers have to serve the UEs
in a way that these requirements are not
violated. Thus, in NOMOR’s simulator we have
proposed the scheduler to support a QoS-aware
metric, [4][6], defined as:
α
GBR (n ) ω d (n , t )
mQoS (n , t ) =
R (n , t ) P (n )
where R(n,t) is the average throughout of the
flow n, P(n) is the priority of the flow n and α is
a scalar factor used to emphasize the influence
of the rate ratio in mQoS . ωd(n,t) is the delay
coefficient and is defined as:
d (n , t )
ω d (n , t ) = exp β HOL
D
Pr ofile (n )
where dHOL(n,t) is the head of line (HOL) delay of
the flow n at time t, DProfile is the delay
requirement of the flow n defined by its QoS
profile, and β is a scalar factor used to enhance
the effect of the exponential.
However, in a REN the definition of the
scheduling metric is just part of the entire
process. In order to assure that QoS
requirements are fulfilled for the R-UEs, we also
have to take care that the data reaches the RN
on time. Hence, multiplexing of the backhaul link
is a key issue. A simple way to realize that is to
consider at the DeNB, from a scheduling
perspective, the backhaul link as a normal link,
with the QoS requirements of all underlying
flows merged into single “super flow” for each
QCI: for each distinct QoS type used by the RUEs we create a super flow with an aggregate
rate requirement corresponding to the sum of all
sub-flows (n) belonging to this flow type.
RB ≥ ∑ Rn
Furthermore, the delay requirement for the
created “super flow” is defined as
DQoS − DeNB =
D profile
2
,
This latter equation enforces the maximum
allowed delay in each of the two scheduling
round to be halved. This forces the scheduler to
send the packet before what it normally would to
offer the second scheduler the possibility of
delivering the data before the packet deadline.
NOMOR’s LTE-A Simulation Capabilities
In this section, we introduce NOMOR’s LTE-A
simulator capabilities with regard to relay
operation. Figure 3 depicts the architecture of
the LTE-Advanced relay testbed devedloped by
NOMOR within the scope of the EU funded
ARTIST4G research project. We note that the
testbed is composed of the following nodes:
NCE, eNB, UE, MME, Gateway, and RNs.
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5. ASN.1 encoding, UDP and IP connectivity,
timing, tracing, configuration etc. The gateways
are responsible for terminating the connection
between the eNB or UE to the core network.
Figure 3: LTE-A testbed block diagram with RNs
A. Testbed nodes
The NOMOR Channel Emulator (NCE) is the
responsible for emulating the physical conditions
of the radio links. Among other functionalities it
is reponsible for:
Configuration of the physical channel depending
on the antenna pattern, cell layout, transmission
power, etc.;
Generation of the channel state information
such as RSRP and SINR;
Decoding of the allocation information from the
eNB/RN to generate interference information;
Estimation of BLER.
The NCE has been tested and is fully compliant
with the 3GPP channel model requirements.
The NOMOR eNB is a full protocol stack
implementation develop under C++ enviroment
as
a
multi-layered
and
multi-threaded
application. It consists of the L2 protocol stack
(i.e. the PDCP, RLC, and MAC layer), the L3 radio
resource control (i.e. the RRC layer), the L3 S1Application Protocol (i.e. S1AP-Layer), the L3 X2Application Protocol (i.e. X2AP-Layer), the userplane interface to the EPC (i.e. the S1-U
interface), and the OAM module providing some
basic OAM functionality and also coupling
possibility with an external OAM module.
The NOMOR’s UE emulator is implemented in a
similar way as the eNB and contains the
counterapert of the eNB radio interfaces.
The NOMOR MME emulator and the NOMOR S/P-GW are implemented using C++ as a
monolithic and multi-layered application. The
MME also includes other system facilities for
B. Relay implementation
NOMOR’s relay node implementation is a mix of
the NOMOR’s eNB protocol and the NOMOR’s UE
emulator. The current relay implementation
supports the following main functions:
UEs (M-UEs) can attach directly to DeNB or to
the RNs;
The RN appears as a UE to DeNB and as a eNB
to its UEs (R-UEs) ;
Necessary MBSFN sub-frame modifications for
MAC operation;
The RNs have their own cell ids;
In-band mode of operation via MBSFN subframes;
Out-band mode of operation via carrier
aggregation functionalities;
Proportional Fair scheduling for UEs attached to
an eNB/RN
Different types of partitioning of resources
between RNs and UEs
R-PDCCH allocation when there are R-UEs
present
C. Scheduler implementation
Our QoS scheduler is composed of two main
parts. The main function of the so-called Time
Domain (TD) scheduler is to create a candidate
list of users that will be scheduled in this
scheduling round. First, the users are sorted
according to their QoS-metric. For sake of
complexity, the TD scheduler limits the number
of users that will be forwarded to the next
phase. The list is then forwarded to the
Frequency Domain (FD) scheduler which is
responsible for the allocation of the frequency
resource units to the users in the candidate list:
all the resources are visited one by one and the
user with the best metric is allocated the
particular resource unit. After the allocation of
each resource unit, the average throughput of
the allocated user is updated and the allocation
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6. process is repeated for the other resource units
until all resources have been allocated or no data
is available on the transmitting buffers.
D. Traffic generator
NOMOR’s traffic generatoris is an IP-based traffic
creator that can be configured to work in various
modes for example:
Full-buffer in which the traffic generator
constantly checks for the buffer levels and it
always keeps them above a pre-configured
threshold;
Constant Bit-rate (CBR) mode in which the
traffic
generator
creates
packets
deterministically in intervals which depend on
the bitrate configured for each traffic.
For simplicity the NOMOR’s traffic generator is
implemented in the PDCP layer of the DeNB
protocol stack.
Key Simulation Results
A. Deployment Scenario
The performance evaluation of the proposed
strategies is conducted using protocol level
simulations, i.e. all the procedures are standard
compliant. Nevertheless, the radio links are
emulated by modelling the physical channel. The
used channel model complies with the 3GPP
Case 1 for urban macro cells with an ISD of
500m, as specified in [7].
Our deployment scenario consists of a single
macro cell with 1 DeNB and 2 RNs attached to it.
Within the macro cell, a so-called “hot-spot”
scenario is assumed: 25 UEs are placed such
that a pair of 2 UEs (the R-UEs) always ends up
in the coverage region of each RN and the
remaining 21 UEs (the M-UEs) in the coverage
region of the DeNB. In addition, all UEs are
periodically relocated randomly within their
respective coverage regions.
In the case of out-band relaying two 5 MHz
carriers will be used for this evaluation while in
the case of in-band relaying a single 10 MHz
carrier is deployed.
B. Traffic Model
For the resource partition simulations no explicit
QoS requirements are defined. Hence, we have
used a full buffer traffic generated.
For the QoS simulations two main traffic types
were defined:
VoIP traffic: emulated using a CBR traffic
generator of 128 kbps. In order to emulate real
QoS conditions, this type of traffic has a
maximum end-to-end of 100 ms and the service
priority is defined as 2 in the scheduler [7];
Video streaming traffic: emulated as a 256 kbps
CBR service with a maximum packet end-to-end
delay of 300 ms and the service priority of 5.
C.
Performance Analysis
a) Resource partition
Figure 4 contains the resource partition results
for out-band relaying compared to DeNB-only
with carrier aggregation, i.e., the case where no
RN is active and all 25 UEs are connected
directly to the DeNB. As can be observed, for the
given deployment scenario with 2 RNs, a
significant performance gain is possible over the
whole range of throughput values with any of
the proposed resource allocation strategies.
Nevertheless, Ext-Prop-Fair seems to be the
preferred solution due to its unified framework
and best performance in the low and medium
range.
When comparing in-band relaying to DeNB-only
without carrier aggregation, we also observe a
similar relative gain in Figure 5. However, from a
system perspective, the preferred strategy is not
that obvious: While Fair-RU achieves better
performance across all UEs, we have noticed
during our simulations that due to overcompensation of backhaul link, it penalizes the
M-UEs, making the Fair-TP scheme more
attractive.
In general outband backhaul using carrier
aggregation at the Donor eNB outperforms
inband signalling, partly due to better link
adaptation in two carriers. Nevertheless it should
be noted that the PDCCH overhead required to
enable parallel scheduling in two carriers or cross
carrier scheduling has not been considered in the
simulation.
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7. Figure 4: Out-band case: Throughput CDF of the
all UEs for different strategies vs. DeNB only
case.
Figure 5: In-band case: Throughput CDF of the
all UEs for different strategies vs. DeNB only
case.
b) QoS provisioning
In this sub-section, we present some simulation
results with regard to QoS provisioning in relay
enhanced networks using an inband backhaul
link. To this end, we consider a traffic mix of
voice and streaming users with distinct QoS
requirements as defined earlier.
In Figure 6 and Figure 7, we present the
achieved throughput and delay CDFs for these
services respectively for the conventional (static
resource partitioning) scheme and the proposed
QoS-aware scheduling scheme.
We observe that for conventional scheme in
Figure 6, especially the M-UEs fail to achieve
their QoS requirements. The throughput CDF in
Figure 6 (a) shows that 5%-ile throughput
values of VoIP and video M-UEs are 89.5 kbps
and 102.5 kbps compared to the traffic bit rates
of 128 kbps and 256 kbps respectively.
Furthermore, in the delay CDF in Figure 6 (b),
we observe the 95%-ile delays for the two traffic
types to be 133 ms and 373 ms compared to the
maximum allowed latency of 100 ms and 300
ms.
With the proposed QoS-aware resource
allocation scheme, the QoS satisfaction of all
users improve, as can be seen in Figure 7. We
observe that 5%-ile throughput values of VoIP
and video M-UEs increase to 126.5 kbps and
194.5 kbps, while the corresponding 95%-ile
packet delays reduce to 87 ms and 297 ms
respectively. Significant overall gain is observed,
since
backhaul
resources
are
assigned
dynamically based on RN-UE’s QoS constrains
instead of a fixed assignment based on the
number of RN-UEs only.
In order to summarize the effectiveness of the
proposed QoS-aware resource allocation scheme
for relay enhanced networks, we present in
Table 1 a comparison with the conventional
scheme, in terms of the fraction of satisfied
users. It can be seen that especially for M-UEs,
the fraction of satisfied users is appreciably
increased by employing the proposed QoS-aware
resource allocation scheme. For instance, the
number of satisfied video UEs increases from
8.1% to 88.8% w.r.t. the achieved throughput
and from 74.7% to 95.3% w.r.t. the experienced
packet delay.
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8. (a)
(b)
Figure 6 DeNB+2RN scenario with conventional resource allocation (static resource partition plus
proportional fair scheduler): Throughput and Delay CDF comparison for different UE groups (M-UEs
and R-UEs) and traffic type (VoIP and Video).
(a)
(b)
Figure 7 DeNB+2RN scenario with proposed QoS-aware resource allocation: Throughput and Delay
CDF comparison for different UE groups (M-UEs and R-UEs) and traffic type (VoIP and Video).
Conclusions
In this white paper, we considered the
problem of resource allocation in relay
enhanced networks. First, we addressed the
fundamental question of how to split the
resources at DeNB between the macro-access
and the backhaul link. Next, we proposed and
demonstrated mechanisms to provide QoS
support to users in relay enhanced networks,
highlighting the various additional challenges
that must be considered in relaying scenarios.
Furthermore, we throw some light on the
capabilities of the NOMOR’s LTE-A simulator
which is a powerful tool for simulating relay
related issues and is based on a 3GPP
compliant
channel
model.
Some
representative results obtained from this
simulator have been included in this white
paper. In summary, outband transmission to
the relay nodes in combination with carrier
aggregation proved to be very efficient. For
resource partitioning, we observed that FairTP and ExtPropFair schemes manage to
achieve a good balance between throughput
gain and effect on the direct users however
the latter involves less changes into the
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9. existing scheduler. On the other hand, for
QoS provisioning, we demonstrated that our
novel QoS-aware resource allocation proposal
brings appreciable gains in terms of backhaul
resource usage and user satisfaction.
Table 1. DeNB+2RN scenario: Fraction of satisfied users for the proposed QoS-aware (Prop.) vs. the
conventional static resource partitioning based (Conv.) resource allocation
UE Type
Fraction of satisfied users w.r.t
achieved throughput
experienced delay
Conv.
Prop.
Conv.
Prop.
Video M-UES
8.1%
88.8%
74.7%
95.3%
VoIP M-UEs
80.0%
99.4%
90.5%
99.0%
Video R-UEs
100%
100%
100%
100%
VoIP R-UES
100%
100%
100%
100%
References
[1]
REPORT ITU-R M.2134 - Requirements
related to technical performance for IMTAdvanced radio interface(s).
[2]
3GPP TR 36.912 V9.1.0 (2009-12),
Feasibility study for Further Advancements for EUTRA (LTE-Advanced).
[3]
G. Liebl, T. M. de Moraes, A. Soysal, and
E. Seidel, “Fair Resource Allocation for Inband
Relaying in LTE-Advanced,” in 2011 8th
International Workshop on Multi-Carrier Systems
& Solutions (MC-SS), Herrsching, Germany, May
2011.
[4]
T. Martins de Moraes, , M. D. Nisar, A.
Gonzalez, and E. Seidel, “Resource Allocation in
Relay Enhanced LTE Networks”, in EURASIP
Journal on Wireless Communications and
Networking, 2012 (Submitted)
[5]
G. Liebl, T. Martins de Moraes, A.
Gonzalez, A. Soysal, and E. Seidel, “Fair
Resource Allocation for the Relay Backhaul Link
IEEE
Wireless
in
LTE-Advanced,”
in
Communications and Networking Conference
(WCNC 2012), Paris, France, Apr 2012.
[6]
T. Martins de Moraes, A. Gonzalez, M. D.
Nisar, and E. Seidel, “QoS-aware Resource
Allocation for In-band Relaying in LTEAdvanced,” in Eighth International Conference
on Wireless and Mobile Communications (ICWMC
2012), Venice, Italy, Jun 2012.
[7]
3GPP TR 36.814 V9.0.0 (2010-03),
“Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio
Access (E-UTRA); Further advancements for EUTRA physical layer aspects, (Release 9),”
Technical Report 3GPP, 2010.
Note: This white paper is provided to you by Nomor
Research GmbH. Similar documents can be obtained from
www.nomor.de. Feel free to forward this issue in
electronic format. Please contact us in case you are
interested in collaboration on related subjects.
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10. System Level Simulation Services
Nomor Research has developed a comprehensive
simulation environment supporting various
standards such as LTE, LTE Advanced and HSPA
and offers related services to support research,
development and standardisation.
Features of the dynamic multi-cell, multi-user
system level simulator include:
• macro-cell and HetNet deployments (pico-,
femto-cell, relay nodes)
• flexible base station and user configurations
and drop models
• different transmitter and receiver chains incl.
MIMO, ZF, MMSE
• channel modeling with slow/fast fading,
pathloss, full user mobility
• intra- and intercell interference modeling for
OFDMA, SC-FDMA and WCDMA
• 2D and 3D antenna pattern and multiantenna beam forming
• Extensive metrics and KPIs: capacity,
throughput, spectral efficiency, user QoS etc
The simulator can be used on project basis or in
customized
simulation
campaigns.
The
performance of the system level simulator has
been calibrated to simulation results obtained in
standardisation.
Research on advanced algorithms include, but
are not limited to:
• advanced features as link adaptation, HARQ,
power control, measurements
• scheduling
and
resource
allocation
algorithms considering channel and buffer
status, QoS etc.
• inter-cell
interference
coordination,
avoidance and cancellation
• Single user-, multi-user MIMO with open and
closed loop feedback
• Cooperative multi-point transmission and
reception
• functions for self-organising and selfoptimizing networks (e.g. load balancing,
mobility optimization, tilt optimisation, range
extension, power saving etc. )
If you are interested in our services please
contact us at info@nomor.de or visit us at
http://www.nomor-research.com/simulation
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