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
More filters
TL;DR: Simulation results show that, given a moderate MS transmit power, the proposed MR-FFR-DAS architecture employing the SC-PDA receiver is capable of achieving significantly better bit error rate (BER) and effective throughput across the entire cell- edge area, including even the worst-case direction and the cell-edge boundary, than the CoMP-CAS architecture.
Abstract: Coordinated multi-point transmission/reception aided collocated antenna system (CoMP-CAS) and mobile relay assisted fractional frequency reuse distributed antenna system (MR-FFR-DAS) constitute a pair of virtual-MIMO based technical options for achieving high spectral efficiency in interference-limited cellular networks. In practice both techniques have their respective pros and cons, which are studied in this paper by evaluating the achievable cell-edge performance on the uplink of multicell systems. We show that assuming the same antenna configuration in both networks, the maximum available cooperative spatial diversity inherent in the MR-FFR-DAS is lower than that of the CoMP-CAS. However, when the cell-edge MSs have a low transmission power, the lower-complexity MR-FFR-DAS relying on the simple single-cell processing may outperform the CoMP-CAS by using the proposed soft-combining based probabilistic data association (SC-PDA) receiver, despite the fact that the latter scheme is more complex and incurs a higher cooperation overhead. Furthermore, the benefits of the SC-PDA receiver may be enhanced by properly selecting the MRs' positions. Additionally, we show that the performance of the cell-edge MSs roaming near the angular direction halfway between two adjacent RAs (i.e. the "worst-case direction") of the MR-FFR-DAS may be more significantly improved than that of the cell-edge MSs of other directions by using multiuser power control, which also improves the fairness amongst cell-edge MSs. Our simulation results show that given a moderate MS transmit power, the proposed MR-FFR-DAS architecture employing the SC-PDA receiver is capable of achieving significantly better bit-error rate (BER) and effective throughput across the entire cell-edge area, including even the "worst-case direction" and the cell-edge boundary, than the CoMP-CAS architecture.
3 citations
Cites background or methods from "LTE-advanced: next-generation wirel..."
...Hence, in this paper, we aim for investigating the pros and cons of a pair of representative cellular architectures, namely, the coordinated multipoint transmission/reception [2]–[11] aided collocated antenna system (CoMP-CAS) and the fractional frequency reuse [12]–[14] assisted distributed antenna system relying on mobile relays (MR-FFR-DAS), in the context of the multicell uplink....
[...]
...As a remedy, CoMP techniques [2]–[11] have been advocated for...
[...]
...However, when aiming for supporting gigabit transmissions, which is the ambitious goal of LTE-A standard [2], the high-rate fiber-based backhaul may suffer from the detrimental effects of...
[...]
Journal Article•
TL;DR: It is demonstrated how CA can be used as an enabler for simple yet effective frequency domain interference management schemes and the quality of service (QoS) performances of two different multi-u ser scheduling schemes in CA based LTE-A systems are compared.
Abstract: Carrier aggregation (CA) is one of the main feature s in Long Term Evolution‐ Advanced (LTE-A). CA will allow the target peak data rates in excess of 1 Gbps in the downlink and 500 Mbps in the uplink t o be achieved and the users can have access to the total bandwidth of up to 100 MHz. The system bandwidth may be continuous or system consisting of several p arts of non-continuous aggregated bandwidth. This paper provides a summary of the supported CA scenarios as well as an overview of the advanced functionality of CA-LTE with particular emphasis on the basic concept, control mechanisms, and the performance aspects of (CA). This paper also demonstrates how CA can be used as an enabler for simple yet effective frequency domain interference management schemes. In particular, the interference management is to provide the intervention made sign ificant gains in heterogeneous networks, envisionin g intrinsically uncoordinated deployments from the ho me base stations. Then, we compared the quality of service (QoS) performances of two different multi-u ser scheduling schemes in CA based LTE-A systems, separated random user scheduling (SRUS) and joint user scheduling (JUS). The former is simpler but les s efficient, whereas the latter is optimal but with h igher overheadsignaling. Moreover, only one single component carrier (CC) is required to access for us er equipment (UE) in the case of SRUS, while all th e CCs must be connected in the case of JUS. Some technical challenges for implementing carrier schedulin g schemes technique in LTE-A systems, are discussed and highlighted.
3 citations
21 Nov 2013
TL;DR: A green radio resource allocation (GRRA) scheme for LTE-A downlink systems with coordinated multi-point (CoMP) transmission to support multimedia traffic and enhances the system throughput by 5.5% and improves the Jain fairness index for best effort users by 155% over these two schemes.
Abstract: In this paper, we propose a green radio resource allocation (GRRA) scheme for LTE-A downlink systems with coordinated multi-point (CoMP) transmission to support multimedia traffic. It is a crucial issue to find a balance between throughput maximization and transmission power minimization, especially when the QoS requirement guarantee for multimedia traffic is considered. The GRRA scheme defines a green radio utility function by considering required transmission power, assigned modulation order, and coordinated transmission nodes. Based on this utility function, it coordinates transmission nodes to deliver data on suitable subchannels with suitable transmission power. Simulation results show that, the GRRA scheme can save the transmission power by 33.9% and 40.1%, as compared to the adaptive radio resource allocation scheme [5] with CoMP and the utility-based radio resource allocation scheme [6] with CoMP, respectively. Besides, it enhances the system throughput by 5.5% and improves the Jain fairness index for best effort users by 155% over these two schemes.
3 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Long term evolution-advanced (LTE-A) has been introduced by 3rd generation partnership project (3GPP) to fulfill requirements of IMT-advanced for next-generation cellular systems [1]....
[...]
Posted Content•
TL;DR: This paper proposes a new radio access scheme, namely non-orthogonal interference-free radio access (No-INFRA), which enables the collision-free reception of uncoordinated access requests and turns the problem of decomposing geometric sequence decomposition into one of solving a th order polynomial equation.
Abstract: This paper presents a computationally efficient technique for decomposing non-orthogonally superposed $k$ geometric sequences. The method, which is named as geometric sequence decomposition with $k$-simplexes transform (GSD-ST), is based on the concept of transforming an observed sequence to multiple $k$-simplexes in a virtual $k$-dimensional space and correlating the volumes of the transformed simplexes. Hence, GSD-ST turns the problem of decomposing $k$ geometric sequences into one of solving a $k$-th order polynomial equation. Our technique has significance for wireless communications because sampled points of a radio wave comprise a geometric sequence. This implies that GSD-ST is capable of demodulating randomly combined radio waves, thereby eliminating the effect of interference. To exemplify the potential of GSD-ST, we propose a new radio access scheme, namely non-orthogonal interference-free radio access (No-INFRA). Herein, GSD-ST enables the collision-free reception of uncoordinated access requests. Numerical results show that No-INFRA effectively resolves the colliding access requests when the interference is dominant.
3 citations
25 Apr 2016
TL;DR: New signal constellation designs are investigated to mitigate fading correlation and maximize the capacity and error performance of multiuser MIMO MU-MIMO over correlated channels, which is a major research challenge.
Abstract: Channels' correlation has direct impact to degrade the capacity and reliability of multiple-input multiple-output MIMO systems considerably. In this paper, new signal constellation designs are investigated to mitigate fading correlation and maximize the capacity and error performance of multiuser MIMO MU-MIMO over correlated channels, which is a major research challenge. Two methods are studied in a novel constellation constrained MU-MIMO approach, namely, unequal power allocation and rotated constellation. Based on principles of maximizing the minimum Euclidean distance dmin of composite received signals, users' data can be recovered using maximum likelihood joint detection irrespective of correlation values. Compared with the identical constellation scenario in conventional MU-MIMO, it is shown that constellation rearrangement of transmitted signals has direct impact to resolve the detection ambiguity when the channel difference is not sufficient, particularly in moderate to high correlations. Extensive analysis and simulation results demonstrate the superiority of proposed technique to capture most of the promised gains of multiantenna systems and application for future wireless communications. Copyright © 2014 John Wiley & Sons, Ltd.
3 citations
References
More filters
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]....
[...]