scispace - formally typeset
Search or ask a question

Showing papers on "LTE Advanced published in 2011"


Book
21 Mar 2011
TL;DR: In this article, the authors focus on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system, including the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance.
Abstract: Based on the bestseller "3G Evolution - HSPA and LTE for mobile broadband" and reflecting the ongoing success of LTE throughout the world, this book focuses on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system. Overview and detailed explanations are given for the latest LTE standards for radio interface architecture, the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, advanced radio resource management and protocols, and different radio network architectures. Their role and use in the context of mobile broadband access in general is explained. Both a high-level overview and more detailed step-by-step explanations of the LTE/LTE-Advanced implementation are given. An overview of other related systems such as GSM/EDGE, HSPA, CDMA2000, and WIMAX is also provided. This book is a 'must-have' resource for engineers and other professionals in the telecommunications industry, working with cellular or wireless broadband technologies, giving an understanding of how to utilize the new technology in order to stay ahead of the competition. The authors of the book all work at Ericsson Research and have been deeply involved in 3G and 4G development and standardisation since the early days of 3G research. They are leading experts in the field and are today still actively contributing to the standardisation of LTE within 3GPP. Includes full details of the latest additions to the LTE Radio Access standards and technologies up to and including 3GPP Release 10Clear explanations of the role of the underlying technologies for LTE, including OFDM and MIMO Full coverage of LTE-Advanced, including LTE carrier aggregation, extended multi-antenna transmission, relaying functionality and heterogeneous deploymentsLTE radio interface architecture, physical layer, access procedures, MBMS, RF characteristics and system performance covered in detail

1,845 citations


Journal ArticleDOI
TL;DR: The technology enhancements introduced to LTE in Release 10, carrier aggregation, improved multi-antenna support, relaying, and improved support for heterogeneous deployments, are described and simulation results show that LTE Release 10 fulfills and even exceeds the requirements for IMT-Advanced.
Abstract: This article provides a high-level overview of LTE Release 10, sometimes referred to as LTE-Advanced. First, a brief overview of the first release of LTE and some of its technology components is given, followed by a discussion on the IMT-Advanced requirements. The technology enhancements introduced to LTE in Release 10, carrier aggregation, improved multi-antenna support, relaying, and improved support for heterogeneous deployments, are described. The article is concluded with simulation results, showing that LTE Release 10 fulfills and even surpasses the requirements for IMT-Advanced.

354 citations


Journal ArticleDOI
TL;DR: This article presents a summary of the supported CA scenarios as well as an overview of the CA functionality for LTE-Advanced with special emphasis on the basic concept, control mechanisms, and performance aspects and demonstrates how CA can be used as an enabler for simple yet effective frequency domain interference management schemes.
Abstract: Carrier aggregation is one of the key features for LTE-Advanced. By means of CA, users gain access to a total bandwidth of up to 100 MHz in order to meet the IMT-Advanced requirements. The system bandwidth may be contiguous, or composed of several non-contiguous bandwidth chunks that are aggregated. This article presents a summary of the supported CA scenarios as well as an overview of the CA functionality for LTE-Advanced with special emphasis on the basic concept, control mechanisms, and performance aspects. The discussion includes definitions of the new terms primary cell (PCell) and secondary cell (SCell), mechanisms for activation and deactivation of CCs, and the new cross-CC scheduling functionality for improved control channel optimizations. We also demonstrate how CA can be used as an enabler for simple yet effective frequency domain interference management schemes. In particular, interference management is anticipated to provide significant gains in heterogeneous networks, envisioning intrinsically uncoordinated deployments of home base stations.

263 citations


Book
07 Feb 2011
TL;DR: From GSM to LTE: An Introduction to Mobile Networks and Mobile Broadband enables readers to examine and understand each technology, and how to utilise several different systems for the best results as discussed by the authors.
Abstract: A new edition of Wiley's Communication Systems for the Mobile Information Society, from the same authorWireless systems such as GSM, UMTS, LTE, WiMAX, Wi-Fi and Bluetooth offer possibilities to keep people connected while on the move. In this flood of technology, From GSM to LTE: An Introduction to Mobile Networks and Mobile Broadband enables readers to examine and understand each technology, and how to utilise several different systems for the best results. This book contains not only a technical description of the different wireless systems available today, but also explains the rationale behind the different mechanisms and implementations; not only the 'how' but also the 'why' is focused on. Thus the advantages and also limitations of each technology become apparent.Offering a solid introduction to major global wireless standards and comparisons of the different wireless technologies and their applications, this new edition has been updated to provide the latest directions and activities in 3GPP standardization reaching up to Release 10, and importantly includes a new chapter on LTE. The new LTE chapter covers aspects such as Mobility Management and Power Optimization, Voice over LTE, and Air Interface and Radio Network.Provides readers with an introduction to major global wireless standards and compares the different wireless technologies and their applications The performance and capacity of each system in practice is analyzed and explained, accompanied with practical tips on how to discover the functionality of different networks Offers approximately 25% new material, which includes a major new chapter on LTE and updates to the existing material including Release 4 BICN in relation to GSM Questions at the end of each chapter and answers on the accompanying website (http://www.wirelessmoves.com) make this book ideal for self study or as course material

178 citations


Proceedings ArticleDOI
Kenta Okino1, Taku Nakayama1, Chiharu Yamazaki1, Hirotaka Sato1, Yoshimasa Kusano1 
05 Jun 2011
TL;DR: This paper investigates performance of CRE with various bias settings and shows that a moderate bias setting is effective to enhance capacity and user throughput and proposes to support coordination of Lightly Loaded CCH transmission Subframe (LLCS) in LTE-Advanced.
Abstract: Deploying Pico eNodeBs (PeNBs) throughout a Macro cell layout is a promising solution to enhance system capacity and user throughput. However, strong received power from Macro eNodeBs (MeNBs) makes the Pico cell areas narrow. This causes limited cell splitting gain. Cell Range Expansion (CRE), which allows a User Equipment (UE) to be served by a cell with weaker received power, is simple and typical one of alternative cell associations to enhance offloading but it causes downlink (DL) interference issue in not only data and also control channels (CCHs). In this paper, we investigate performance of CRE with various bias settings and show that a moderate bias setting is effective to enhance capacity and user throughput. With respect to the DL interference issue in CCHs, we propose to support coordination of Lightly Loaded CCH transmission Subframe (LLCS) in LTE-Advanced.

157 citations


Proceedings ArticleDOI
28 Mar 2011
TL;DR: Reliable D2D multicast concept introduced in this paper is designed to be scalable and efficient solution for local communication needs such as file transfer and even streaming services.
Abstract: In this paper we introduce a reliable multicast concept for Device-to-Device (D2D) communication integrated into cellular network. In addition to the introduction of the basic concept, initial simulation results are presented as well. Clustering closely located devices which have local communication needs is a feasible and efficient way of solving the increasing data traffic requirements in the future cellular network. Reliable D2D multicast concept introduced in this paper is designed to be scalable and efficient solution for local communication needs such as file transfer and even streaming services. Due to the network involvement in controlling the local D2D communication, sufficient quality of service can be guaranteed. In addition, due to the flexible mode switching between direct and cellular modes in the integrated operation the service continuity can be provided.

123 citations


Journal ArticleDOI
TL;DR: It is shown that MU-MIMO only offers marginal performance gains with respect to single-user MIMO and calls for improved schemes for the upcoming releases.
Abstract: A relatively recent idea of extending the benefits of MIMO systems to multiuser scenarios seems promising in the context of achieving high data rates envisioned for future cellular standards after 3G (3rd Generation). Although substantial research has been done on the theoretical front, recent focus is on making Multiuser Multiple-Input Multiple-Output (MUMIMO) practically realizable. This paper presents an overview of the different MU-MIMO schemes included/being studied in 3GPP standardization from LTE (long-term evolution) to LTE Advanced. MU-MIMO system concepts and implementation aspects have been studied here. Various low-complexity receiver architectures are investigated, and their performance assessed through link-level simulations. Appealing performance offered by low-complexity interference aware (IA) receivers is notably emphasized. Furthermore, system level simulations for LTE Release 8 are provided. Interestingly, it is shown that MU-MIMO only offers marginal performance gains with respect to single-user MIMO. This arises from the limited MU-MIMO features included in Release 8 and calls for improved schemes for the upcoming releases.

123 citations


Book
04 Aug 2011
TL;DR: This practical, one-stop guide will quickly bring you up to speed on LTE and LTE-Advanced with everything you need to know about the theory and technology behind the standards.
Abstract: This practical, one-stop guide will quickly bring you up to speed on LTE and LTE-Advanced. With everything you need to know about the theory and technology behind the standards, this is a must-have for engineers and managers in the wireless industry. First book of its kind describing technologies and system performance of LTE-A Covers the evolution of digital wireless technology, basics of LTE and LTE-A, design of downlink and uplink channels, multi-antenna techniques and heterogeneous networks Analyzes performance benefits over competing technologies, including WiMAX and 802.16m Reflects the latest LTE Release-10 standards Includes numerous examples, including extensive system and link results Unique approach is accessible to technical and non-technical readers alike

117 citations


Posted Content
TL;DR: The key features encompassing the physical layer, network layer and back-hauling aspects of time-domain ICIC in Rel-10 are surveyed.
Abstract: Heterogeneous networks (het-nets) - comprising of conventional macrocell base stations overlaid with femtocells, picocells and wireless relays - offer cellular operators burgeoning traffic demands through cell-splitting gains obtained by bringing users closer to their access points. However, the often random and unplanned location of these access points can cause severe near-far problems, typically solved by coordinating base-station transmissions to minimize interference. Towards this direction, the 3rd generation partnership project Long Term Evolution-Advanced (3GPP-LTE or Rel-10) standard introduces time-domain inter-cell interference coordination (ICIC) for facilitating a seamless deployment of a het-net overlay. This article surveys the key features encompassing the physical layer, network layer and back-hauling aspects of time-domain ICIC in Rel-10.

98 citations


Proceedings Article
27 Apr 2011
TL;DR: Three cell selection methods associated with ICIC in heterogeneous networks in the LTE-Advanced downlink are investigated: signal-to-interference plus noise power ratio (SINR)-based cell selection, reference signal received power (RSRP)-basedcell selection, andreference signal received quality (RSRQ)-based Cell selection.
Abstract: In LTE-Advanced, a heterogeneous network where femtocells and picocells overlaid onto macrocells is extensively discussed in addition to traditional well-planned macrocell deployment to improve further the system throughput. In heterogeneous network deployment, cell selection as well as intercell interference coordination (ICIC) is very important to improve the system and cell-edge throughput. Therefore, this paper investigates three cell selection methods associated with ICIC in heterogeneous networks in the LTE-Advanced downlink: signal-to-interference plus noise power ratio (SINR)-based cell selection, reference signal received power (RSRP)-based cell selection, and reference signal received quality (RSRQ)-based cell selection. Simulation results (4 pico eNodeBs and 25 set of user equipment are uniformly located within 1 macro eNodeB) assuming full buffer model show that the downlink cell and cell-edge user throughput levels of RSRP-based cell selection are degraded by approximately 3% and 10% compared to those of SINR-based cell selection under the condition of the maximizing the cell-edge user throughput due to the impairment of the interference level. Furthermore, it is shown that the downlink cell-edge user throughput of RSRQ-based cell selection is improved approximately 5%, although the cell throughput is degraded approximately 5% compared to that for SINR-based cell selection under the condition of the maximizing the cell-edge user throughput.

97 citations


Journal ArticleDOI
B. A. Bjerke1
TL;DR: The fourth generation (4G) wireless technology known as Long Term Evolution (LTE) allows cellular operators to use new and wider spectrum and complements third generation (3G) networks with higher user data rates, lower latency, and a flat Internet Protocol (IP)-based network architecture.
Abstract: The fourth generation (4G) wireless technology known as Long Term Evolution (LTE) allows cellular operators to use new and wider spectrum and complements third generation (3G) networks with higher user data rates, lower latency, and a flat Internet Protocol (IP)-based network architecture. The LTE standard was first published in March 2009 as part of the Third Generation Partnership Project (3GPP) Release 8 specifications. The specifications have been in development since 2005 when 3GPP defined LTE requirements and performance goals to significantly improve on the 3GPP Release 6 standard, which was at that point the state of the art. Achieving those goals required an evolution of both the air interface and the network architecture, now known as Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and Evolved Packet Core (EPC), respectively. The very first commercial LTE networks were deployed on a limited scale in Scandinavia at the end of 2009, and currently, large-scale deployments are taking place in several regions, including North America, Europe, and Asia.

Proceedings ArticleDOI
15 May 2011
TL;DR: A handover optimization algorithm based on the UE's mobility state is proposed and the comparison between the proposed algorithm and the traditional handover control algorithm shows that the algorithms proposed have aSignalling overhead reduction in the signalling overhead.
Abstract: Femtocell is a small access point using the wire broadband connections or wireless technologies to access the mobile operator's network for the user equipment(UE), which can provide better indoor coverage and satisfy the upcoming demand of high data rate for wireless communication system.Femtocell related handover cost reduction is one of the important targets in LTE-Advanced SON (Self-Organising Networks). In this paper, a handover optimization algorithm based on the UE's mobility state is proposed. An analytical model was presented for the handover signalling cost analysis. Numerical results are provided to compare the signalling cost of different handover management schemes. The comparison between the proposed algorithm and the traditional handover control algorithm shows that the algorithms proposed in this paper have a significant reduction in the signalling overhead.

Journal ArticleDOI
TL;DR: Using various advanced technologies such as interference mitigation techniques, MIMO, and cooperative communications as well as cross-layer self-organizing networks, it is shown that future urban wireless networks could potentially offer high-quality mobile services and offer an experience similar to the wired Internet.
Abstract: In this article we present a survey on the technical challenges of future radio access networks beyond LTE-Advanced, which could offer very high average area throughput to support a huge demand for data traffic and high user density with energy-efficient operation. We highlight various potential enabling technologies and architectures to support the aggressive goal of average area throughput 25 Gb/s/km2 in beyond IMT-Advanced systems. Specifically, we discuss the challenges and solutions from the controlling/ processing perspective, the radio resource management perspective, and the physical layer perspective for dense urban cell deployment. Using various advanced technologies such as interference mitigation techniques, MIMO, and cooperative communications as well as cross-layer self-organizing networks, we show that future urban wireless networks could potentially offer high-quality mobile services and offer an experience similar to the wired Internet.

Proceedings ArticleDOI
01 Nov 2011
TL;DR: This paper evaluates the performance of ICIC and CRE in picocell deployments in the LTE-Advanced downlink and shows that when the CRE offset value is set between 8 to 20 dB, almost the same user throughput performance is obtained by allocating the appropriate resources to protect UEs that connect to the picocells.
Abstract: In Long-Term Evolution (LTE)-Advanced, heterogeneous networks where femtocells and picocells are overlaid onto macrocells are extensively discussed in addition to traditional well-planned macrocell deployment to improve further the system throughput. In heterogeneous network deployment, combined usage of inter-cell interference coordination (ICIC) and cell range expansion (CRE) is very effective in improving the system and cell-edge throughput. In this combined usage, the fraction of the sets of user equipment (UEs) connected to the picocells, which are controlled through CRE, and that connected to macrocells affect the gain from the ICIC. Therefore, this paper evaluates the performance of ICIC and CRE in picocell deployments in the LTE-Advanced downlink. Simulation results (4 picocells and 30 UEs are located within 1 macrocell) assuming a full buffer model show that when the CRE offset value is set between 8 to 20 dB, almost the same user throughput performance is obtained by allocating the appropriate resources to protect UEs that connect to the picocells.

Proceedings Article
27 Apr 2011
TL;DR: This paper presents a M2M system architecture based on LTE/LTE-A and highlights the delays associated with each part of the system and proposals on how the latency can be further reduced are described.
Abstract: Machine-to-machine communication has attracted a lot of interest in the mobile communication industry and is under standardization process in 3GPP. Of particular interest is LTE-Advanced support for various M2M service requirements and efficient management and handling of a huge number of machines as mobile subscribers. In addition to the higher throughput, one of the main advantages of LTE/LTE-A in comparison with the previous cellular networks is the reduced transmission latency, which makes this type of networks very attractive for real-time mobile M2M communication scenarios. This paper presents a M2M system architecture based on LTE/LTE-A and highlights the delays associated with each part of the system. Three real-time M2M applications are analyzed and the main latency bottlenecks are identified. Proposals on how the latency can be further reduced are described.

Proceedings ArticleDOI
Wang Jun1, Jianguo Liu1, Dongyao Wang1, Jiyong Pang1, Gang Shen1 
01 Dec 2011
TL;DR: In 3GPP LTE-A heterogeneous network scenario, the system-level performance evaluation shows that the proposed optimized fairness cell selection methods could achieve significant performance gains especially for the cell edge users.
Abstract: Pico cell has been brought to cellular networks as a new technology to deliver cost-effective coverage and capacity to hard-to-reach places, and also increase capacity by cell splitting in hotspots with very dense phone usage. However, according to existing strongest receiving signal association method, pico cells with the extremely low transmitting power are significantly limited in the presence of macro coverage. Thus, the new introduced pico frequency resource will not be fully exploited in this unbalanced user distributions among macro and pico cells. In this paper, by jointly considering the long term channel condition and load balance in this macro-pico coexisted heterogeneous network, we formulate the cell selection problem into a network-wide proportional fairness optimization. Both optimal solution (by dynamic programming) and cost efficient algorithm (greedy heuristics) are proposed. In 3GPP LTE-A heterogeneous network scenario, the system-level performance evaluation shows that, compared with the conventional strongest signal cell selection scheme, the proposed optimized fairness cell selection methods could achieve significant performance gains especially for the cell edge users.

Journal ArticleDOI
TL;DR: An overview of these uplink MIMO schemes is presented, along with their impact on reference signals and DL control signaling, and their link performances are compared.
Abstract: The evolution of LTE uplink transmission toward MIMO has recently been agreed in 3GPP, including the support of up to four-layer transmission using precoded spatial multiplexing as well as transmit diversity techniques. In this article, an overview of these uplink MIMO schemes is presented, along with their impact on reference signals and DL control signaling. Receivers suitable for uplink MIMO are presented, and their link performances are compared.

Proceedings ArticleDOI
01 Jan 2011
TL;DR: Simulation results show that the proposed adaptive bias configuration strategy for RE can improve the cell edge performance compared with the static bias setting strategies, while maintaining the overall cell performance.
Abstract: The coexistence of macro eNodeBs and the additional low power nodes (LPNs) may lead to much higher interference in LTE-Advanced Heterogeneous Networks (HetNets) In Macro Pico scenario, Range Extension (RE) is a promising scheme to utilize the LPN resources more effectively and improve the cell edge performance However, it may introduce more interference if the bias value is not properly set In this paper, an adaptive bias configuration strategy for RE is proposed In this strategy, the bias value is set adaptively according to the environment variability, which contains three stages including bias initialization, system performance feedback and dynamic bias value setting The proposed scheme aims to make the RE scheme adaptive and improve the cell edge users' performance through cell load balance Simulation results show that the proposed scheme can improve the cell edge performance compared with the static bias setting strategies, while maintaining the overall cell performance

Proceedings ArticleDOI
01 Sep 2011
TL;DR: This article presents how such B4G systems will look like and some key technologies they will rely on including versatile numerology, massive virtual MIMO from many base stations, both centralized and distributed architectures using fiber optics as backbone, advanced interference mitigation, cognitive self organization, and wideband RF radios.
Abstract: Mobile communication systems have evolved over the past decades and each new generation brought new experience to the users enabled by technology innovations, while keeping some well established principles from previous generations. This trend continued up to LTE (Long Term Evolution) Advanced, the predominant 4th generation system which has just been standardized in 3GPP and is being rolled out soon. How will this trend continue to future systems which will be deployed in some 10 years from now which will be advanced enough to be called “Beyond 4G” (B4G)? This article presents how such B4G systems will look like and some key technologies they will rely on including versatile numerology, massive virtual MIMO from many base stations, both centralized and distributed architectures using fiber optics as backbone, advanced interference mitigation, cognitive self organization, and wideband RF radios.

Proceedings ArticleDOI
05 Jun 2011
TL;DR: System simulations results for an FTP traffic model indicate that, for a pico cell deployment with density of 4 picos per macro cell, 40% or more performance gain can be achieved when techniques enabling cell range expansion are deployed.
Abstract: This paper discusses the need and enabling mechanisms for a heterogeneous deployment model in LTE networks, where lower power nodes are deployed in a macro network. Cell range expansion, enabled through cell biasing and adaptive resource partitioning, is seen as an effective method to balance the load among the nodes in the network and to improve overall trunking efficiency. Interference cancellation receiver plays a crucial role to ensure acquisition of weak cells and reliability of control and data reception in the presence of legacy signal. System simulations results for an FTP traffic model indicate that, for a pico cell deployment with density of 4 picos per macro cell, 40% or more performance gain can be achieved when techniques enabling cell range expansion are deployed.

Proceedings ArticleDOI
01 Dec 2011
TL;DR: Simulation results show that the proposed G-factor based carrier selection algorithm can achieve much better coverage performance compared to the least-load carrier selection in scenarios with relatively high inter-site distance and relatively high frequency separation between carriers, at the expense of some marginal average user throughput loss.
Abstract: Carrier aggregation (CA) is one of the most distinct features for LTE-Advanced systems, which can support a much wider transmission bandwidth up to 100 MHz by aggregating two or more individual component carriers (CCs) belonging to the same (intra-band) or different (inter-band) frequency bands. With CA, it is possible to schedule a user equipment (UE) on multiple CCs simultaneously. From radio resource management (RRM) perspective, CC selection plays an important role in optimizing the system performance, especially in the case of inter-band CA where the radio propagation characteristics of each CC can be different. In this paper, we investigate the downlink resource allocation for inter-band CA, i.e., how to assign carrier(s) to different UEs. A simple yet effective G-factor based carrier selection algorithm, which takes both traffic load and radio channel characteristics into considerations, is proposed with the objective to guarantee good coverage for Rel'8 UEs and robustness for Rel'10 UEs. Simulation results show that our proposed G-factor based carrier selection algorithm can achieve much better coverage performance compared to the least-load carrier selection in scenarios with relatively high inter-site distance and relatively high frequency separation between carriers, at the expense of some marginal average user throughput loss.

Journal ArticleDOI
TL;DR: An overview of the interference coordination strategies in OFDM-based multihop cellular networks and several typical static or semi-static interference coordination schemes are proposed to improve the coverage and increase the cell edge data rate.
Abstract: Recently there has been an upsurge of interests in the multihop infrastructures for orthogonal frequency division multiplexing-based cellular networks in both academia and industry. In this article, we first present an overview of the interference coordination strategies in OFDM-based multihop cellular networks. Then, based on the framework of third-generation LTE-Advanced networks with multihop relaying, several typical static or semi-static interference coordination schemes are proposed to improve the coverage and increase the cell edge data rate. By applying these schemes, the radio resources can be reused with certain limitations on either the frequency or time domain, or even both of them. Dynamic system-level simulations are also carried out to demonstrate the effectiveness of the proposed interference coordination schemes.

Journal ArticleDOI
TL;DR: The various technology components like wideband transmission and spectrum sharing, multiantenna solutions, coordinated multiple transmission/reception (CoMP) and relaying, introduced to meet the requirements for LTE Advanced systems, have been discussed.
Abstract: By the design and optimization of upcoming radio access techniques and a further evolution of the existing system, the Third Generation Partnership Project (3GPP) had laid down the foundations of the future Long Term Evolution (LTE) advanced standards-the 3GPP candidate for 4G. This paper offers an overview of the research work carried out to meet the requirements of 4G. The various technology components like wideband transmission and spectrum sharing, multiantenna solutions, coordinated multiple transmission/reception (CoMP) and relaying, introduced to meet the requirements for LTE Advanced systems, have been discussed.

Proceedings ArticleDOI
15 May 2011
TL;DR: A mathematical model of the log-measure utility in an LTE-Advanced system is provided, and proof that the previously developed cross-CC Proportional Fair (PF) packet scheduler maximizes this utility is given.
Abstract: Long Term Evolution (LTE)-Advanced is expected to aggregate multiple Component Carrier (CC)s to fulfil the high data rate requirement. It may serve users with different capabilities in accessing these CCs, e.g., some can access all CCs, whereas some may operate on only one CC. This gives challenges to the packet scheduler to maximize the system performance over all CCs. In this paper we provide a mathematical model of the log-measure utility in an LTE-Advanced system, and give proof that our previously developed cross-CC Proportional Fair (PF) packet scheduler maximizes this utility. System level simulations are performed, which confirm that cross-CC PF scheduling offers much higher utility than independent PF and channel blind schedulers. This scheduler is then generalized to adjust the resource sharing among users. It can trade off between average cell throughput and cell edge user throughput. However, any adjustment in the resource sharing leads to a loss in utility.

Patent
02 Nov 2011
TL;DR: In this paper, the interference coordination problem between macro BSs and pico user equipments (UEs) is addressed based on the concept of almost blank subframe (ABS), which is supported by the LTE-A standard.
Abstract: The Long Term Evolution Advanced (LTE-A) network, is a heterogeneous network, where macro and pico base stations (BSs) coexist to improve spectral efficiency per unit area. Systems and methods described herein attempt to provide a solution to the interference coordination problem between macro BSs and pico user equipments (UEs). Specifically, the systems and methods conduct interference coordination based on the concept of almost blank subframe (ABS), which is supported by the LTE-A standard. The macro BSs choose their ABS configurations in a cooperative way such that the overall system throughput is optimized.

Patent
14 Sep 2011
TL;DR: In this paper, a method for reporting uplink control information (UCI) on a user equipment (UE) is described, where a collision between a hybrid automatic repeat request acknowledgement (HARQ-ACK) and a channel quality indicator/precoding matrix index/rank indication is detected.
Abstract: A method for reporting uplink control information (UCI) on a user equipment (UE) is described. It is determined whether a collision between a hybrid automatic repeat request acknowledgement (HARQ-ACK) and a channel quality indicator/precoding matrix index/rank indication (CQI/PMI/RI) is detected. It is also determined whether a simultaneousAckNackAndCQI parameter provided by higher layers is set to TRUE. The UCI is generated with the HARQ-ACK using physical uplink control channel (PUCCH) Format 3.

Proceedings ArticleDOI
Stefan Brueck1
01 Nov 2011
TL;DR: The need for an alternative deployment model and topology using heterogeneous networks and advanced techniques, which are needed to manage and control interference and deliver the full benefits of such networks are described.
Abstract: 3GPP Long-term Evolution (LTE) allows operators to use new and wider spectrum and complements 3G networks with higher data rates, lower latency and a flat, IP-based architecture. To further improve the broadband user experience in an ubiquitous and cost-effective manner, 3GPP has been working on various aspects of LTE-Advanced. Since radio link performance is quickly approaching theoretical limits with 3G enhancements and LTE, the next performance leap will come from an evolved network topology. This paper discusses the need for an alternative deployment model and topology using heterogeneous networks. The concept of LTE-Advanced based heterogeneous networks is about improving spectral efficiency per unit area. Using a mix of macro, pico, femto and relay cells, heterogeneous networks enable flexible and low-cost deployments and provide a uniform broadband experience. To enhance the performance of these networks, advanced techniques are described, which are needed to manage and control interference and deliver the full benefits of such networks. These techniques include cell range expansion, adaptive inter cell interference coordination and interference cancellation receivers.

Proceedings ArticleDOI
Liu Liu1, Mingju Li1, Juejia Zhou1, Xiaoming She1, Lan Chen1, Yuta Sagae1, Mikio Iwamura1 
15 May 2011
TL;DR: The proposed CC management method is shown by simulation results to be effective in providing comparable user throughput with lower implementation complexity, as compared to solely ingenious resource allocation.
Abstract: This paper focuses on investigating appropriate management of Component Carriers(CCs) in carrier aggregation( CA) system, which is identified as one of the most distinct features of 4G systems including Long Term Evolution- Advanced (LTE-A). An LTE-A user equipment (UE) is allowed to concurrently utilize multiple carriers, which leads to scalable increase in user throughput. However, in certain circumstances, aggregating entire available carriers for a UE is not meaningful due to probably low channel quality or high traffic load in some of the CCs. Therefore, how to make good use of multiple carriers in real deployment scenarios is an important issue. Based on the analysis of resource allocation across multiple carriers in Layer-2, two CC management methods in Layer- 3 are proposed. The proposed method is shown by simulation results to be effective in providing comparable user throughput with lower implementation complexity, as compared to solely ingenious resource allocation.

Proceedings ArticleDOI
01 Dec 2011
TL;DR: An improved CC selection method for non-continuous CA is proposed and results demonstrate that the proposed method outperforms both of the traditional ones.
Abstract: In order to meet the requirement of wider bandwidth in IMT-Advanced, carrier aggregation (CA) is introduced by 3GPP to support bandwidth up to 100MHz in its LTE-Advanced standards. An LTE Rel.10 UE can aggregate up to 5 component carriers (CCs) simultaneously, but may be assigned only part of the total available CCs depending on its capability or traffic load. Thus, a proper CC selection method is necessary. First, two traditional CC selection methods respectively named Random and Round Robin CC selection are investigated, which can well balance the load across different CCs. However, neither of them is suitable for non-continuous CA scenarios through our analysis. To solve this problem, an improved CC selection method for non-continuous CA is proposed in this paper. Simulation results demonstrate that the proposed method outperforms both of the traditional ones.

Proceedings ArticleDOI
12 May 2011
TL;DR: Simulation results show that performance measures in terms of the system throughput, the mean delay, and the fairness are much better than those of a system in which component carriers are not aggregated but used independently.
Abstract: Carrier Aggregation (CA) is one of the promising features to support the much wider bandwidth for packet transmissions in Long Term Evolution-Advanced (LTE-A) systems. To the best of our knowledge, works regarding the packet scheduling algorithm in LTE-A systems with the CA mechanism have not thoroughly been investigated yet till now. In this paper, we therefore aim to design an efficient packet scheduling algorithm based on the proportional fair criterion in such environment. We focus on downlink transmissions supporting both Real-Time (RT) and non-RT traffics simultaneously. Simulation results show that performance measures in terms of the system throughput, the mean delay, and the fairness are much better than those of a system in which component carriers are not aggregated but used independently.