Carrier aggregation for LTE-advanced mobile communication systems
TL;DR: In this paper, a brief review of continuous and non-continuous CA techniques is given, followed by two data aggregation schemes in physical and medium access control layers, and possible technical solutions for the asymmetric CA problem, control signaling design, handover control and guard band setting are reviewed.
Abstract: In order to achieve up to 1 Gb/s peak data rate in future IMT-Advanced mobile systems, carrier aggregation technology is introduced by the 3GPP to support very-high-data-rate transmissions over wide frequency bandwidths (e.g., up to 100 MHz) in its new LTE-Advanced standards. This article first gives a brief review of continuous and non-continuous CA techniques, followed by two data aggregation schemes in physical and medium access control layers. Some technical challenges for implementing CA technique in LTE-Advanced systems, with the requirements of backward compatibility to LTE systems, are highlighted and discussed. Possible technical solutions for the asymmetric CA problem, control signaling design, handover control, and guard band setting are reviewed. Simulation results show Doppler frequency shift has only limited impact on data transmission performance over wide frequency bands in a high-speed mobile environment when the component carriers are time synchronized. The frequency aliasing will generate much more interference between adjacent component carriers and therefore greatly degrades the bit error rate performance of downlink data transmissions.
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05 Feb 2014
TL;DR: Measurements and capacity studies are surveyed to assess mmW technology with a focus on small cell deployments in urban environments and it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities.
Abstract: Millimeter-wave (mmW) frequencies between 30 and 300 GHz are a new frontier for cellular communication that offers the promise of orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multielement antenna arrays. This paper surveys measurements and capacity studies to assess this technology with a focus on small cell deployments in urban environments. The conclusions are extremely encouraging; measurements in New York City at 28 and 73 GHz demonstrate that, even in an urban canyon environment, significant non-line-of-sight (NLOS) outdoor, street-level coverage is possible up to approximately 200 m from a potential low-power microcell or picocell base station. In addition, based on statistical channel models from these measurements, it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities. Cellular systems, however, will need to be significantly redesigned to fully achieve these gains. Specifically, the requirement of highly directional and adaptive transmissions, directional isolation between links, and significant possibilities of outage have strong implications on multiple access, channel structure, synchronization, and receiver design. To address these challenges, the paper discusses how various technologies including adaptive beamforming, multihop relaying, heterogeneous network architectures, and carrier aggregation can be leveraged in the mmW context.
2,452 citations
Cites background from "Carrier aggregation for LTE-advance..."
... to any one cell will be inherently unreliable and can rapidly change with small motions of the users or the user’s environment. One avenue to explore is the use carrier aggregation techniques [109], [110] where mobiles can connect to multiple base stations simultaneously. Carrier aggregation was introduced in release 10 of 3GPP LTE-Advanced primarily to increase peak throughputs. For mmW systems, carr...
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TL;DR: This paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NomA.
Abstract: Non-orthogonal multiple access (NOMA) is one of the promising radio access techniques for performance enhancement in next-generation cellular communications. Compared to orthogonal frequency division multiple access, which is a well-known high-capacity orthogonal multiple access technique, NOMA offers a set of desirable benefits, including greater spectrum efficiency. There are different types of NOMA techniques, including power-domain and code-domain. This paper primarily focuses on power-domain NOMA that utilizes superposition coding at the transmitter and successive interference cancellation at the receiver. Various researchers have demonstrated that NOMA can be used effectively to meet both network-level and user-experienced data rate requirements of fifth-generation (5G) technologies. From that perspective, this paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMA. In addition, this paper discusses how NOMA performs when it is integrated with various proven wireless communications techniques, such as cooperative communications, multiple-input multiple-output, beamforming, space-time coding, and network coding among others. Furthermore, this paper discusses several important issues on NOMA implementation and provides some avenues for future research.
1,406 citations
Cites background from "Carrier aggregation for LTE-advance..."
...In order to increase the BW, and thereby, increase the data rate of its users, LTE-Advanced utilizes the concept of carrier aggregation (CA) [71]....
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TL;DR: In this paper, the authors comprehensively survey the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMAs.
Abstract: Non-orthogonal multiple access (NOMA) is one of the promising radio access techniques for performance enhancement in next-generation cellular communications. Compared to orthogonal frequency division multiple access (OFDMA), which is a well-known high-capacity orthogonal multiple access (OMA) technique, NOMA offers a set of desirable benefits, including greater spectrum efficiency. There are different types of NOMA techniques, including power-domain and code-domain. This paper primarily focuses on power-domain NOMA that utilizes superposition coding (SC) at the transmitter and successive interference cancellation (SIC) at the receiver. Various researchers have demonstrated that NOMA can be used effectively to meet both network-level and user-experienced data rate requirements of fifth-generation (5G) technologies. From that perspective, this paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the state-of-the-art capacity analysis, power allocation strategies, user fairness, and user-pairing schemes in NOMA. In addition, this paper discusses how NOMA performs when it is integrated with various proven wireless communications techniques, such as cooperative communications, multiple input multiple output (MIMO), beamforming, space time coding, and network coding, among others. Furthermore, this paper discusses several important issues on NOMA implementation and provides some avenues for future research.
879 citations
TL;DR: The suitability of millimeter wave beamforming methods, both, existing and proposed till midyear 2015, are explored, and the exciting new prospects unfolding in this domain are identified.
Abstract: The remarkable growth of wireless data traffic in recent times has driven the need to explore suitable regions in the radio spectrum to meet the projected requirements. In pursuance of this, millimeter wave communications have received considerable attention in the research fraternity. Due to the high path and penetration losses at millimeter wavelengths, antenna beamforming assumes a pivotal role in establishing and maintaining a robust communication link. Beamforming for millimeter wave communications poses a multitude of diverse challenges due to the large channel bandwidth, unique channel characteristics, and hardware constraints. In this paper, we track the evolution and advancements in antenna beamforming for millimeter wave communications in the context of the distinct requirements for indoor and outdoor communication scenarios. We expand the scope of discussion by including the developments in radio frequency system design and implementation for millimeter wave beamforming. We explore the suitability of millimeter wave beamforming methods, both, existing and proposed till midyear 2015, and identify the exciting new prospects unfolding in this domain.
557 citations
Cites methods from "Carrier aggregation for LTE-advance..."
...It is envisaged that millimeter wave cellular systems will be HetNets [192], [193] incorporating carrier aggregation techniques [194] to enable macro-diversity in order to counter the...
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TL;DR: This article provides a tutorial overview of 3GPP LTE-Advanced with carrier aggregation as specified in Rel-10 including deployment scenarios of interest, main design features, PHY/MAC procedures, and potential enhancements for future standard releases.
Abstract: To satisfy the ever increasing demand for higher throughput and data rates, wireless communication systems need to operate in wider bandwidths 3GPP LTE-Advanced with carrier aggregation enables operators to maximally and optimally utilize their available spectrum resources for increased data rates and user experience while reducing their incurred OPEX and CAPEX This article provides a tutorial overview of 3GPP LTE-Advanced with carrier aggregation as specified in Rel-10 including deployment scenarios of interest, main design features, PHY/MAC procedures, and potential enhancements for future standard releases
312 citations
Cites background from "Carrier aggregation for LTE-advance..."
...Carrier aggregation [4] [5] [6], where multiple component carriers of smaller bandwidth are aggregated, is an attractive alternative to increase data rate....
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References
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15 Apr 2008
TL;DR: A preliminary look at an efficient downlink control channel design to reduce the overhead required to support data transmission and initial performance results show that close to optimal system performance can be achieved with down link control overhead of less than 14%.
Abstract: With the emergence of packet-based wireless broadband systems, 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 including control channel is envisioned. This paper provides a preliminary look at an efficient downlink control channel design to reduce the overhead required to support data transmission. Initial performance results show that close to optimal system performance can be achieved with downlink control overhead of less than 14%.
97 citations