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: In order to reduce signaling overhead of the proposed scheme, a number of joint discrete-rate adaptation and relay selection approaches are proposed for both non-reciprocal and reciprocal channels.
Abstract: This paper presents a novel joint rate adaptation and relay selection scheme for multi-relay networks adopting half-duplex best-relay decode-and-forward protocol. The proposed scheme aims to maximize the overall transmission rate when relays are allowed to forward messages using different rates from the source. It is shown that the proposed scheme outperforms the conventional adaptive scheme in terms of the spectral efficiency (e.g. by 10.1% improvement for SNR=10 dB). Furthermore, in order to reduce signaling overhead of the proposed scheme, a number of joint discrete-rate adaptation and relay selection approaches are proposed for both non-reciprocal and reciprocal channels. The relay selection is basically a two-stage scheme. At the rm first stage, a set of relays are selected based on mixed channel quality information (CQI), i.e., the knowledge of CQI varies for different links; at the second stage, the best relay within the set is selected based on instantaneous CQI, which is obtained through carefully designed signaling protocols. It is shown that the proposed discrete-rate adaptation schemes can offer comparable spectral efficiency to the conventional adaptive scheme with significantly reduced signaling overhead.
13 citations
Cites background from "LTE-advanced: next-generation wirel..."
...For example in European 3GPP long-term evolution (LTE-Advanced) [9], wireless relays are deployed to enhance coverage of cellular services....
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TL;DR: In this article, a joint transmitter and receiver design for pattern division multiple access (PDMA) is proposed, where pattern mapping utilizes power allocation to improve the overall sum rate and beam allocation to enhance the access connectivity.
Abstract: In this paper, a joint transmitter and receiver design for pattern division multiple access (PDMA) is proposed. At the transmitter, pattern mapping utilizes power allocation to improve the overall sum rate, and beam allocation to enhance the access connectivity. At the receiver, hybrid detection utilizes a spatial filter to suppress the inter-beam interference caused by beam-domain multiplexing, and successive interference cancellation to remove the intra-beam interference caused by power-domain multiplexing. Furthermore, we propose a PDMA joint design approach to optimize pattern mapping based on both the power domain and beam domain. The optimization of power allocation is achieved by maximizing the overall sum rate, and the corresponding optimization problem is shown to be convex theoretically. The optimization of beam allocation is achieved by minimizing the maximum of the inner product of any two beam allocation vectors, and an effective dimension reduction method is proposed through the analysis of pattern structure and proper mathematical manipulations. Simulation results show that the proposed PDMA approach outperforms the orthogonal multiple access and power-domain non-orthogonal multiple access approaches even without any optimization of pattern mapping, and the optimization of beam allocation yields a significant performance improvement than the optimization of power allocation.
13 citations
TL;DR: This paper proposes the scheme called OFDM with all index modulation (OFDM-AIM), which replaces the PSK/QAM constellation modulator with subblock modulator and simplifies the structure and is capable of achieving better BER performance than other index modulated OFDM schemes.
Abstract: In recent years, OFDM with index modulation (OFDM-IM) has become a potential technique due to its improvement of diversity gain. In typical OFDM-IM schemes, incoming information bits are divided into two parts, symbols bits, and index bits. However, the symbol bits conveyed by each OFDM symbol suffer from low diversity order, which has a negative impact on diversity gain. In this paper, we propose the scheme called OFDM with all index modulation (OFDM-AIM), which replaces the PSK/QAM constellation modulator with subblock modulator and simplifies the structure. With such an arrangement, the subblocks of OFDM-AIM become flexible, which contributes to achieving the higher diversity order of the system. Moreover, we study the effects of Euclidean distance and diversity order based on the unconditional pair error probability, which gives the guideline to design a legitimate subblocks set. Then the algorithm to build the subblocks set with higher diversity order is proposed, which can achieve better diversity gain. Theoretical and simulated results show that the OFDM-AIM scheme is capable of achieving better BER performance than other index modulated OFDM schemes.
13 citations
Cites methods from "LTE-advanced: next-generation wirel..."
...In the standards of LTE, OFDM is regarded as core technique in downlink transmission [5]....
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Patent•
15 Apr 2011
TL;DR: In this article, a two-way relaying with beamforming is described, which includes estimating communications channels between a relay and communications devices coupled to the relay, storing data contained in the transmissions, precoding a transmission including a subset of the stored data with a precoding matrix, and transmitting the precoded transmission.
Abstract: A system and method for two-way relaying with beamforming are provided. A method for relay operations includes estimating communications channels between a relay and communications devices coupled to the relay, storing data contained in the transmissions, storing data contained in the transmissions, precoding a transmission including a subset of the stored data with a precoding matrix, and transmitting the precoded transmission. The estimating is based on transmissions made by the communications devices in the subset of communications devices, and the precoding matrix is based on estimates of the communications channels.
13 citations
TL;DR: An intelligent heartbeat monitoring system to detect the possibility of arrhythmia in real time and achieve an average accuracy of 97% in heartbeat detection and an average heartbeat classification accuracy of above 96%, which is comparable with the best competing schemes.
Abstract: Background: The automatic interpretation of electrocardiography (ECG) data can provide continuous analysis of heart activity, allowing the effective use of wireless devices such as the Holter monitor. Materials and Methods: We propose an intelligent heartbeat monitoring system to detect the possibility of arrhythmia in real time. We detected heartbeats and extracted features such as the QRS complex and P wave from ECG signals using the Pan–Tompkins algorithm, and the heartbeats were then classified into 16 types using a decision tree. Results: We tested the sensitivity, specificity, and accuracy of our system against data from the MIT-BIH Arrhythmia Database. Our system achieved an average accuracy of 97% in heartbeat detection and an average heartbeat classification accuracy of above 96%, which is comparable with the best competing schemes. Conclusions: This work provides a guide to the systematic design of an intelligent classification system for decision support in Holter ECG monitoring.
13 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Conversely, LTE technologies, while more expensive, support highmobility devices and have broad coverage.(34) If monitoring systems can reuse existing LTE infrastructure, then the initial cost of deployment is greatly reduced....
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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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