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 2014
TL;DR: In this article, the basic concepts of antenna parameters and principles of circularly polarized antennas are discussed. But, the reader is not familiar with the antenna basics, and the basic antenna types for circular polarization are presented.
Abstract: Chapter 1 introduces the reader to basic concepts of antenna parameters and principles of circularly polarized antennas. This can help readers who are not familiar with the antenna basics. In the first part of the chapter, the main antenna parameters such as radiation pattern, gain, polarization, circular polarization, efficiency, bandwidth, and so on are explained. In the second part of the chapter, basic antenna types for circular polarization are presented. These include CP patch antennas, crossed dipoles, helix antennas, QHA, PQHA, spiral antennas, slot antennas, dielectric resonator antennas, patch arrays, and slot arrays. The operation principles of each type of CP antenna are explained. The third part of the chapter discusses typical requirements and challenges in CP antenna designs, followed by a brief summary and a list of references.
40 citations
28 Jul 2014
TL;DR: It is shown that for a prototype 28 GHz mmWave system, the self-interference from the TX sector panel to the adjacent RX panel is around -70 to -80 dB and an additional 35-50 dB isolation is needed for enabling reception on adjacent RXPanel that may be achieved through full duplex interference cancellation techniques.
Abstract: Next generation wireless backhaul systems may provide data rates exceeding 10 Gb/s using large bandwidth available at mmWave frequencies, and support features such as point-to-multipoint communication, non-line-of-sight communication, in-band operation (shared spectrum with access) and inter-BS coordination. We explore the feasibility of an “in-band” mmWave wireless base-station with the option of enabling backhaul transmission on one panel while simultaneously receiving access or backhaul on an adjacent panel. We show using simulations and lab measurement validation, that for a prototype 28 GHz mmWave system, the self-interference from the TX sector panel to the adjacent RX panel is around -70 to -80 dB and an additional 35-50 dB isolation is needed for enabling reception on adjacent RX panel that may be achieved through full duplex interference cancellation techniques.
39 citations
Cites background from "LTE-advanced: next-generation wirel..."
...There has been increased effort to provide higher data rates for cellular systems with 4G LTE-A technologies [2] and this growth is likely to continue for future 5G evolution with requirements for Gb/s data rates....
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TL;DR: This paper presents the unlicensed spectrum intercell interference co-ordination (usICIC) mechanism as a time-domain multiplexing technique for interference mitigation for the sharing of an unlicensed channel by multioperator LTE-U small cells and demonstrates that the proposed usICIC mechanism will result in 40% or more improvement in overall LTE- U system performance.
Abstract: The deployment of long term evolution (LTE) in the unlicensed spectrum (LTE-U) has been gaining significant industry momentum in recent months. The US 5-GHz Unlicensed National Information Infrastructure (UNII) bands that are currently under consideration for LTE deployment in the unlicensed spectrum contain only a limited number of 20 MHZ channels. Thus, in a dense multi-operator deployment scenario, one or more LTE-U small cells have to coexist and share the same 20 MHz unlicensed channel with each other and with the incumbent Wi-Fi. In this paper, we present the scenario and demonstrate that in the absence of an explicit interference mitigation mechanism, there will be a significant degradation in the overall LTE-U system performance for LTE-U cochannel coexistence in countries that do not mandate listen-before-talk (LBT) requirements. We then present the unlicensed spectrum intercell interference co-ordination (usICIC) mechanism as a time-domain multiplexing technique for interference mitigation for the sharing of an unlicensed channel by multioperator LTE-U small cells. Through extensive simulation results, we also demonstrate that our proposed usICIC mechanism will result in 40% or more improvement in overall LTE-U system performance.
39 citations
Cites background from "LTE-advanced: next-generation wirel..."
...which are considered far inferior to those offered by licensed cellular wireless technologies such as LTE [14], [17] that offers higher spectral efficiency [10]....
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TL;DR: The proposed multiband antenna consists of a meandered planar inverted-F antenna with an additional branch line for wide bandwidth and a folded-loop antenna that provides a wide bandwidth to cover the hepta-band LTE/GSM/UMTS operation.
Abstract: This paper proposes a multiband antenna for LTE/GSM/UMTS band operation. The proposed antenna consists of a meandered planar inverted-F antenna with an additional branch line for wide bandwidth and a folded-loop antenna. The antenna provides a wide bandwidth to cover the hepta-band LTE/GSM/UMTS operation. The measured 6 dB return loss bandwidth is 169 MHz (793–962 MHz) at the low-frequency band and 1030 MHz (1700–2730 MHz) at the high-frequency band. The overall dimension of the proposed antenna is 55 mm × 110 mm × 5 mm.
39 citations
TL;DR: In this article, a centralized infrastructure-based cognitive radio network, where dynamic TVWS allocation among unlicensed systems is administrated by a spectrum broker, carries out radio-resource management and spectrum trading in real time.
38 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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