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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TL;DR: A computationally efficient hybrid steepest descent Gauss–Seidel (SDGS) joint detection is proposed, which directly estimates the user’s transmitted symbol vector, and can quickly converge to obtain an ideal estimation value with a few simple iterations.
Abstract: Traditional channel estimation algorithms such as minimum mean square error (MMSE) are widely used in massive multiple-input multiple-output (MIMO) systems, but require a matrix inversion operation and an enormous amount of computations, which result in high computational complexity and make them impractical to implement. To overcome the matrix inversion problem, we propose a computationally efficient hybrid steepest descent Gauss–Seidel (SDGS) joint detection, which directly estimates the user’s transmitted symbol vector, and can quickly converge to obtain an ideal estimation value with a few simple iterations. Moreover, signal detection performance was further improved by utilizing the bit log-likelihood ratio (LLR) for soft channel decoding. Simulation results showed that the proposed algorithm had better channel estimation performance, which improved the signal detection by 31.68% while the complexity was reduced by 45.72%, compared with the existing algorithms.
14 citations
TL;DR: In this article, the authors evaluate the achievable cell-edge performance on the uplink of multicell systems and 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 in the CoMP-CAS.
Abstract: The coordinated multipoint transmission/reception aided collocated antenna system (CoMP-CAS) and the 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 (or the multiplexing gain) inherent in the MR-FFR-DAS is lower than that in the CoMP-CAS. However, when the cell-edge mobile stations (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 remote antennas (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 among 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.
14 citations
TL;DR: This Chapter deals with LTE systems and the design of a new reuse scheme, called Soft Frequency Reuse (SFR), that is able to increase the cell capacity that is studied, considering the impact of different scheduling schemes and of different user mobility patterns.
Abstract: Future 4G cellular systems will address the need for capacity increase for the support of diverse services. It is therefore of fundamental importance to design innovative 4G cellular systems able to support the increase in the traffic demand. This Chapter deals with LTE systems and the design of a new reuse scheme, called Soft Frequency Reuse (SFR), that is able to increase the cell capacity that is studied, considering the impact of different scheduling schemes and of different user mobility patterns. A consistent SFR scenario has been implemented in both Ns-3 and OMNeT++ environments. An analytical approach is proposed to evaluate the cell capacity with SFR that has been validated by means of Ns-3 simulations. Finally, OMNeT++ simulations have permitted to highlight the significant impact of the scheduling scheme and user mobility on cell capacity; different mobility patterns have been taken into account.
14 citations
10 Nov 2018
TL;DR: The features of quality control service servicing of flows of the mobile communication network are investigated with the use of partial virtualization of network functions and an architectural solution for organization of service flows in a hybrid environment is proposed.
Abstract: There is an integration of telecommunication systems and distributed computing environment, resulting in a single hybrid environment for telecommunication services. The hybrid environment has the ability to control the information flow process at each stage and ensures compliance with high quality standards. Providing the quality of service to end-users of communication networks depends on quality control at all stages of the service provision. Today, due to the dynamically changing service structure provided to end users, constantly changing requirements for service quality indicators, with increasing traffic volumes, there is a growing need for well-scalable communication systems that meet the needs of end-users, gaining special significance to service management systems. In the article the features of quality control service servicing of flows of the mobile communication network are investigated with the use of partial virtualization of network functions. An architectural solution for organization of service flows in a hybrid environment is proposed, which includes a telecommunication communication network and cloud computing resources that provide maintenance of virtualized functions involved in the organization of service flows. The solution for improvement of the PCRF system as well as a number of procedures that allow ensuring quality control of servicing streams as well as controlling the computing resources of a hybrid system, which work affects the quality of service of the system service flows, is proposed.
14 citations
31 Dec 2012
TL;DR: By introducing autonomous terminal reporting and coordination of broadcast signaling over many RAs, the concepts of a self-organizing, and terminal-centric network are described, which could lead to significantly improved flexibility in the network deployment, reduced downlink transmit power, and reduced control signaling load for the ordinary management of the terminals.
Abstract: This paper highlights the significant evolutionary potential in wireless communication networks, taking account of falling costs of RF hardware and increasing availability of powerful centralized signal processing. This so-called 'cloud of antennas' allows a central radio controller to manage a large number of remote antennas (RAs) with increasing control over their radio and radio access network behavior. By introducing autonomous terminal reporting and coordination of broadcast signaling over many RAs, the concepts of a self-organizing, and terminal-centric network are described. These could lead to significantly improved flexibility in the network deployment, reduced downlink transmit power, and reduced control signaling load for the ordinary management of the terminals. The CoA is also compared with other approaches currently being researched.
14 citations
Cites background from "LTE-advanced: next-generation wirel..."
...inter-cell interference control (ICIC), coordinated multi-point (CoMP) transmission and other such features [2]....
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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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