LTE-advanced: next-generation wireless broadband technology [Invited Paper]
TL;DR: An overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed, which includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, and heterogeneous networks with emphasis on Type 1 and Type 2 relays.
Abstract: LTE Release 8 is one of the primary broadband technologies based on OFDM, which is currently being commercialized. LTE Release 8, which is mainly deployed in a macro/microcell layout, provides improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operation and seamless integration with existing systems. LTE-Advanced (also known as LTE Release 10) significantly enhances the existing LTE Release 8 and supports much higher peak rates, higher throughput and coverage, and lower latencies, resulting in a better user experience. Additionally, LTE Release 10 will support heterogeneous deployments where low-power nodes comprising picocells, femtocells, relays, remote radio heads, and so on are placed in a macrocell layout. The LTE-Advanced features enable one to meet or exceed IMT-Advanced requirements. It may also be noted that LTE Release 9 provides some minor enhancement to LTE Release 8 with respect to the air interface, and includes features like dual-layer beamforming and time-difference- of-arrival-based location techniques. In this article an overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed. This includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, uplink spatial multiplexing including extension to four-layer MIMO, and heterogeneous networks with emphasis on Type 1 and Type 2 relays. Finally, the performance of LTEAdvanced using IMT-A scenarios is presented and compared against IMT-A targets for full buffer and bursty traffic model.
Citations
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Patent•
19 Dec 2013TL;DR: In this article, a method and an apparatus for transmitting control signaling for a non-backward compatible component carrier (NCC) is presented. But the method and apparatus in this paper are different from those in the present paper.
Abstract: The present invention discloses a method and an apparatus for transmitting control signaling. The method includes: determining that a physical downlink shared channel PDSCH transmission scheme for a non-backward compatible component carrier is a user equipment-specific reference signal UE RS-based non-precoding matrix indicator Non-PMI feedback transmission scheme or a UE RS-based up to 8 layer transmission scheme; and sending downlink control information DCI to a UE, where the DCI is used to indicate the determined PDSCH transmission scheme. The apparatus includes a determining module and a first sending module. The method and apparatus in embodiments of the present invention can expand application scenarios of the non-backward compatible component carrier, increase spectrum utilization of the system, and avoid a system capacity decrease problem caused by limitations on the application scenarios of the non-backward compatible component carrier.
14 citations
15 May 2011
TL;DR: In this article, a novel metric, named impact factor, is proposed to represent the impact of control information location selection in the search space of one UE (User Equipment) to other UEs.
Abstract: CA (Carrier aggregation) is one of the most important techniques for LTE-Advanced system because of its capability to support wide bandwidth while achieving backward compatibility. This paper focuses on enhancements of downlink control channel resource allocation for CA system in order to improve the performance of control information transmission in cross-carrier scheduling. A novel metric, named impact factor, is proposed to represent the impact of control information location selection in the search space of one UE (User Equipment) to other UEs. On the basis of the proposed metric, an enhanced control information resource allocation algorithm is proposed to assign control region resource to multiple CCs (Component Carrier) and multiple UEs with low mutual impacts among each other. Furthermore, a novel control information placement method is proposed to solve the problem of active CC set mismatch between eNodeB and UE. Through this novel control information placement after CC activation, data transmission interruptions in cross-carrier scheduling can be effectively reduced. Simulation results show the proposed method can effectively improve the control information transmission performance compared with existing methods.
14 citations
Cites methods from "LTE-advanced: next-generation wirel..."
...Carrier aggregation (CA), which enables bandwidth extension while maintaining backward compatibility, is one of the most important techniques of LTE-Advanced system and extensively discussed in 3GPP [1][2]....
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TL;DR: Several SS approaches for LTE and LTE-A systems are investigated in the CR system and it is found that the two-stage model and the second order cyclostationary algorithms are better than the other algorithms because they produce accurate results at the expense of system complexity.
Abstract: Advanced communication systems, such as long term evolution (LTE) and LTE-advanced (LTE-A) systems, promise to increase the number of users with high-speed data exchange. However, it leads to spectrum scarcity because of the huge size of data exchange with limited spectrum resources. Cognitive radio (CR) technique is considered the best solution for this spectrum scarcity problem. Spectrum sensing (SS), one of the CR techniques is used to detect the spectrum hole of primary user (PU) without interference with PU. In this paper, several SS approaches for LTE and LTE-A systems are investigated in the CR system. These SS approaches are based on two techniques, namely energy detection and cyclostationary feature detection techniques. The first technique includes four approaches of auto-correlation based advanced energy, time domain detection, Welch periodogram and two-stage model algorithms, while the second technique contains two approaches, namely pilot induced cyclostationary and second order cyclostationary algorithms. According to the analysis, the two-stage model and the second order cyclostationary algorithms are better than the other algorithms because they produce accurate results at the expense of system complexity. Hence, in general a good SS algorithms would require some trade-off between complexity and accuracy.
14 citations
04 Jul 2017
TL;DR: A new Mobility Aware downlink Scheduling algorithm (MAS) is proposed and compared with Round Robin and Best-CQI algorithms in terms of throughput, fairness and Block Error Rate (BLER).
Abstract: The Long Term Evolution-Advanced (LTE-A) standard brings together different data and voice communication technologies and allows for the integration of more versatile users and services. To meet the users' needs for high resource demand efficiently, resource scheduling algorithms become even more important, in order to balance good system performance in terms of high throughput and fairness. In this paper, a new Mobility Aware downlink Scheduling algorithm (MAS) is proposed and compared with Round Robin and Best-CQI algorithms in terms of throughput, fairness and Block Error Rate (BLER). Simulation results show that the MAS algorithm not only provides a good balance between throughput and fairness parameters but is also quite robust to mobility.
14 citations
Journal Article•
TL;DR: In this article, the authors consider how the direct X2 connection of evolved base stations (eNBs) on the logical layer can be accommodated with a general centralization of transport networks and show that for LTE, a centralized transport network is able to realize the local meshing between eNBs.
Abstract: Long term evolution technologies provide new standards in mobile communications regarding available bandwidth. It is expected that users of one radio cell will share more than 100 Mbit/s in future. To take advantage of the full feature set of next generation mobile networks, transport network design has to face new requirements, caused by the architectural changes of LTE technologies. Especially the newly defined X2 interface impacts on the transport network requirements. X2 enables direct communication between evolved base stations (eNBs) and thus, enforces local solutions. At the same time a tendency of locating network elements at fewer, central sites to reduce operational expenditure can be observed, in particular concerning the transport layer. This leads to the question of how the direct X2 connection of eNBs on the logical layer can be accommodated with a general centralization of transport networks. Our considerations show that for LTE, a centralized transport network is able to realize the local meshing between eNBs. However, for LTE Advanced, the standards currently discussed by the 3GPP initiative could lead to enhanced requirements on the X2 interface latency. Consequently, the implications for the network architecture have to be analyzed in more detail. Keywords—backhauling, LTE Advanced, mobile network de-
13 citations
References
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01 Sep 2006
TL;DR: A preliminary look at the air interface for Evolved UTRA (E-UTRA) and associated key technologies required to reach its design objectives are provided.
Abstract: With the emergence of packet-based wireless broadband systems such as 802.16e, it is evident that a comprehensive evolution of the universal mobile telecommunications system specifications is required to remain competitive. As a result, work has begun on long term evolution (LTE) of the UMTS terrestrial radio access and radio access network aimed for commercial deployment in 2010. Goals for the evolved system include support for improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To reach these goals, a new design for the air interface is envisioned. This paper provides a preliminary look at the air interface for Evolved UTRA (E-UTRA) and associated key technologies required to reach its design objectives. Initial E-UTRA system performance results show a 2 to 3x improvement over a reference Rel-6 UMTS system configuration [1, 2] for both uplink and downlink.
30 citations
24 Oct 2008
TL;DR: The proposed channel estimation technique is shown to have significant gains in performance compared to other well known channel estimation techniques such as the maximum-likelihood (ML) and the inverse fast Fourier transform (IFFT) channel estimation methods.
Abstract: The performance of the uplink physical channel of the 3GPP LTE system is considered in this paper. Assuming a single user spatial division multiple access transmission scheme, where users' signals are transmitted over different subcarriers, a low complexity channel estimation technique is proposed for the physical uplink shared channel (PUSCH). The proposed channel estimation technique is shown to have significant gains in performance compared to other well known channel estimation techniques such as the maximum-likelihood (ML) and the inverse fast Fourier transform (IFFT) channel estimation methods [5]. Simulation results for different channel models and modulation and coding schemes (MCS) using incremental redundancy (IR) based hybrid automatic repeat request (HARQ) operation are also shown. Finally, a robust detection scheme is proposed for the physical uplink control channel (PUCCH) and simulation results are summarized.
10 citations
"LTE-advanced: next-generation wirel..." refers methods in this paper
...The DFT precoding operation is performed to reduce the cubic metric (CM) of the signal, leading to higher maximum transmit power [2]....
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