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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01 Jan 2015
TL;DR: The capability of full-duplex communications is leveraged to propose novel mechanisms such as full duplex carrier sensing, collision detection, and collision jamming for OFDMA wireless networks.
Abstract: Random medium access control (MAC) plays a critical role in OFDMA wireless networks to support services with bursty traffic. However, the existing OFDMA random access protocols suffer from low efficiency due to the constraints in half-duplex communications. In this paper, the capability of full-duplex communications is leveraged to propose novel mechanisms such as full duplex carrier sensing, collision detection, and collision jamming. With these mechanisms, a full-duplex carrier sense multiple access with collision detection (FD-CSMA/CD) protocol is developed for OFDMA wireless networks. It is based on a hierarchical design: (1) with full-duplex communications, operation of subchannels is decoupled, and a CSMA/CD-like protocol is implemented in each subchannel as a random access scheme; (2) on top of random access per-subchannel, a simple but effective subchannel selection scheme is executed locally on each client to harvest multi-user diversity. Both theoretical analysis and simulations are carried out to validate the effectiveness and efficiency of our protocol.
16 citations
Journal Article•
TL;DR: Despite its simplicity, the model was found to predict channel capacity and bit error rate probability accurately for a typical MU-MIMO- OFDM deployment scenario accurately.
Abstract: Commonwealth Scientific and Industrial Research Organization (CSIRO) has recently conducted a technology demonstration of a novel fixed wireless broadband access system in rural Australia. The system is based on multi user multiple-input multiple-output orthogonal frequency division multiplexing (MU-MIMO-OFDM). It demonstrated an uplink of six simultaneous users with distances ranging from 10 m to 8.5 km from a central tower, achieving 20 bits s/Hz spectrum efficiency. This paper reports on the analysis of channel capacity and bit error probability simulation based on the measured MUMIMO-OFDM channels obtained during the demonstration, and their comparison with the results based on channels simulated by a novel geometric optics based channel model suitable for MU-MIMO OFDM in rural areas. Despite its simplicity, the model was found to predict channel capacity and bit error rate probability accurately for a typical MU-MIMO-OFDM deployment scenario.
16 citations
Cites methods from "LTE-advanced: next-generation wirel..."
...While the use of MU-MIMO has been incorporated in the latest wireless standards, such as Long Term Evolution Advanced (LTE-A) [3], very few implementation works have been so far reported in the literature....
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TL;DR: This work provides a comprehensive review of the existing protocol stacks of IoMT and analyzes their feasibility for multimedia streaming applications and presents an in-home patient monitoring system with an interoperable communication among the connected multimedia streaming devices at home and healthcare practitioners at hospital.
Abstract: Internet of Things (IoT) has widely been accepted as a promising paradigm for connecting a large number of resource-constrained miniature sensor nodes that have the ability to sense the deployed environment. They have found their applications in various aspect of our daily lives. However, these nodes are mostly restricted to sense only the scalar data. Nowadays, multimedia sensor nodes are gaining significant attention due to their ability to collect scalar as well as multi-dimensional data. These nodes are considered as the foundation of Internet of Multimedia Things (IoMT) and are shaping the perception of IoT. Multimedia data have stringent requirements in terms of reliability, latency, storage, bandwidth, and Quality of Service (QoS). To provide seamless and interoperable communication in IoMT, the underlying protocol stacks need to fulfill these stringent requirements. However, the heterogeneous nature of multimedia sensors makes interoperability a challenging task to fulfill. To understand the challenges faced by seamless and interoperable communication in IoMT, we provide a comprehensive review of the existing protocol stacks of IoMT and analyze their feasibility for multimedia streaming applications. Data storage of multimedia applications is another area that requires immediate attention of the research community. For this purpose, we study cloud as an entity to facilitate multimedia applications of IoMT. The instances of multimedia cloud are analyzed and a number of shortcomings are identified that pave the way for edge computing in IoMT. Finally, we present a case study that shows the significance of our work. The case study portrays an in-home patient monitoring system with an interoperable communication among the connected multimedia streaming devices at home, and healthcare practitioners at hospital. The case study also highlights the importance of uninterrupted data storage and retrieval at the network edge and multimedia sensor nodes.
16 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Long Term Evolution-Advanced (LTE-A) is a combination of multiple cellular protocols and is suitable for M2M and IoT data communication over a short-range [46]....
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08 Oct 2012
TL;DR: In this paper, the relay placement problem in an LTE-A network is studied, taking into consideration the effect of co-channel interference, and an optimization framework is proposed to maximize either the total cell capacity or thetotal cell-edge capacity.
Abstract: One of the main problems in LTE-A networks is the small rates achieved by cell-edge users This is due to the adoption of a frequency reuse factor of 1, which aims at increasing the overall capacity This occurs, however, at the expense of increasing the interference level for cell-edge users Cooperative communication through the use of relays is an efficient technique to solve this problem However, careful placement of the relays is a crucial factor in determining the expected capacity gain In this paper, the relay placement problem in an LTE-A network is studied, taking into consideration the effect of co-channel interference An optimization framework is proposed to maximize either the total cell capacity or the total cell-edge capacity Simulation results show a capacity gain factor of 8027 for cell-edge users due to relay deployment, under 100% cell load in center cell and adjacent cells
16 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Amplify-and-Forward (AF) and Decode-and-forward (DF) are the 2 main forwarding techniques in literature, where in the former, the data received by the RS is amplified and retransmitted to UE; while in the later, the data are fully decoded and re-transmitted to the UE....
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TL;DR: It is demonstrated that the integration of the proposed baseband equalizer does not compromise the linearizability of the Doherty PA, and this is the first demonstration of the use of digital equalization for performance enhancement of RF Doherty PAs.
Abstract: This paper introduces a new architecture of frequency-agile Doherty power amplifier (PA)-based RF front-end. This architecture incorporates a baseband equalizer that is implemented using finite-impulse-response (FIR) digital filters to improve the performance of Doherty PAs when driven with large bandwidth and multiband wireless radios. Depending on the center frequency and bandwidth of the input signal, the FIR filters of the proposed equalizer are synthesized to compensate for the nonideal frequency behavior of the RF building blocks of the Doherty PA. It is shown that the proposed architecture enables the Doherty PA to operate with significantly improved power efficiency and linearity performance beyond its nominal frequency of design, which is suitable for multistandard applications. As a matter of fact, when driven with a 140-MHz bandwidth long-term evolution (LTE) signal centered around 2.30 GHz, the average efficiency of a 2.14-GHz Doherty PA prototype with the proposed digital baseband equalizer is enhanced from 33.5% to 44.7%. Moreover, its linearity performance in terms of adjacent channel leakage ratio (ACLR) is improved from $-$ 21 to $-\hbox{26 dB}$ . In addition, when operated in concurrent dual-band mode with two 20-MHz bandwidth LTE signals centered at 1.96 and 2.34 GHz, the proposed Doherty PA enabled a reduction in dc power consumption by nearly 15%. Furthermore, it is demonstrated that the integration of the proposed baseband equalizer does not compromise the linearizability of the Doherty PA. To the best of the authors’ knowledge, this is the first demonstration of the use of digital equalization for performance enhancement of RF Doherty PAs.
16 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Moreover, with the aim of achieving higher data rates, emerging 4G standards (e.g., LTE-Advanced Release 10) are supporting the use of aggregation of component carriers (CCs), which results in creating multicarrier signals with bandwidths up to 100 MHz [14]....
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...This procedure is very useful in practical implantation because the pass-band response of this equalizer 140 MHz already encloses the passband response of any equalizer with lower BW....
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...• Scenario 3: 20-MHz bandwidth LTE signal with 10.9-dB PAPR centered at 2.34 GHz....
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..., LTE-Advanced Release 10) are supporting the use of aggregation of component carriers (CCs), which results in creating multicarrier signals with bandwidths up to 100 MHz [14]....
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...The system consists of one high-speed vector signal generator (VSG) from Rohde & Schwarz Inc. (SMW200A two-channel VSG with maximum baseband extension to 200-MHz RF bandwidth), a dual-input Doherty PA, a vector spectrum analyzer (VSA) from Rohde & Schwarz Inc. (FSW26 with real-time analysis up to 160-MHz bandwidth), and a computer with Matlab software for baseband signal processing....
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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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