Carrier Aggregation

Getting higher data rates always remains a
challenging task and so is in the fifth generation which may
launch in 2021 to get seamless connectivity with ultra-high
speed and extremely low latency less than two milliseconds to
connect mobile devices along with other physical devices which
is about to cross the figure of nine billion over the globe. It is
highly essential to get extremely higher data rates to taste the
fruits of different kinds of services on the mobile handset using
technologies like LTE Advanced Pro, Carrier aggregation
the scheme, and 5G NR. Carrier aggregation will be one of the
better solutions along with massive mimo at the base station to
achieve peak data rates and faster throughput per user. With
5G carrier aggregation, we have 700 MHz bandwidth using
millimeter-wave frequency range which is much higher
compared to 100MHz of LTE advanced to get higher data rates
per user by using advanced higher-order modulation, spatial
multiplexing, and bigger transport block size. More than 1
Gbps data rate can be achieved on the downlink and 500 Mbps on
the uplink. The research paper gives an overall idea of carrier
aggregation in 5G and coexistence with legacy LTE and
Millimeter-wave system.

Long Term Evolution (LTE) is defined by the Third Generation Partnership Project (3GPP) standards as Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users and their applications are increasing, which increases the demand on the system BW. A new feature of the LTE-Advanced (LTE-A) which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA), this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. The main contribution of this paper was in implementing the Intra-band contiguous case by modifying the LTE-Sim-5, then evaluating the Quality of Service (QoS) performance of the Modified Largest Weighted Delay First (MLWDF), the Exponential Rule (Exp-Rule), and the Logarithmic Rule (Log-Rule) scheduling algorithms over LTE/LTE-A in the Down-Link direction. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate (PLR), average packet delay, and fairness among users. Simulation results show that the use of CA improved the system's average throughput, and almost doubled the system's maximum throughput. It reduced the PLR values almost by a half. It also reduced the average packet delay by 20-40\% that varied according to the video bit-rate and the number of users. The fairness indicator was improved with the use of CA by a factor of 10-20%.

Long Term Evolution (LTE) is defined by the Third Generation Partnership Project (3GPP) standards as Release 8/9. The LTE supports at max 20 MHz channel bandwidth for a carrier. The number of LTE users and their applications are increasing, which increases the demand on the system BW.A new feature of the
LTE-Advanced (LTE-A) which is defined in the 3GPP standards as Release 10/11 is called Carrier Aggregation (CA), this feature allows the network to aggregate more carriers in-order to provide a higher bandwidth. Carrier Aggregation has three main cases: Intra-band contiguous, Intra-band non-contiguous, Inter-band contiguous. In addition to the Carrier Aggregation feature, LTE-A supports Heterogeneous Networks (HetNets). HetNets consists of a mix of macro-cells, remote radio heads, and low power nodes such as pico-cells, and femto-cells. HetNets allow cellular network operators to support higher data traffic by offloading it to a smaller cells such as femto-cells. The aim of this paper is to evaluate the Quality of Service (QoS) performance of the Modified Largest Weighted Delay First (MLWDF), the Exponential Rule (Exp-Rule), and the Logarithmic Rule (Log-Rule) scheduling algorithms while offloading 50% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to five femto-cells, 100% of the macro-cell's traffic to ten femto-cells, and to compare it with the case in-which traffic offloading is not applied. The QoS performance evaluation is based on the system's average throughput, Packet Loss Rate (PLR), average packet delay, and fairness among users. The LTE-Sim-5 with modifications is used in the simulation process. Simulation results show that offloading 100% of the Macro-cell's traffic to five femtocells had the highest maximum throughput, and the best PLR values especially when using the Log-Rule, in-which using it maintained the PLR values around 0.15 despite increasing the number of users. The least average packet delay was achieved when offloading 100% of the Macro-cell's traffic to ten femto-cells, the delay dropped to below 5 ms. The fairness indicators for the three scheduling algorithms while traffic offloading was applied fluctuated in a linear way between a range of values of 0.7 and 0.9.

— Traditional wireless and mobile network focuses on higher throughout, coverage and larger capacity. In future, energy efficiency is of vital importance for wireless networks due to a large number of connected and battery constrained mobile devices. In Long Term Evolution Advanced (LTE-Advanced), Carrier Aggregation (CA) is proposed to increase the transmission bandwidth and hence data rate. This paper studies the effect of CA on the total power transmitted by the LTE-Advanced eNodeB based on the Orthogonal Frequency Division Multiple Access (OFDMA) downlink while taking the users Quality of Service (QoS) constraints into consideration. The numerical analysis and results show that by using CA a reduction in total power consumption can be achieved. Keywords— Energy-efficient mobile network; LTE-A; OFDMA downlink; Carrier Aggregation ; QoS.

The initial release of LTE provided extensive support for deployment in spectrum allocations of various characteristics, with bandwidth ranging roughly from 1.3 MHz up to 20 MHz in both paired and unpaired bands. In LTE release 10 the transmission bandwidth can be further extended by means of so-called Carrier Aggregation (CA), where multiple component carriers are aggregated and jointly used for transmission to/from a single terminal. There are up to five component carriers, possibly each of different bandwidth, which can be aggregated, allowing for transmission bandwidth up to 100 MHz backwards compatibility where, each component carrier (CC) uses the release-8 structure. Hence, to a release-8/9 terminal, each CC will appear as an LTE release-8 carrier, while a carrieraggregation capable terminal can exploit the total aggregated bandwidth, enabling higher data rates. In general case, a different number of component carriers can be aggregated for the downlink and uplink. Therefore, this paper highlights the carrier aggregation which supports the inter-band aggregation contiguous component carriers, intra-band aggregation non-contiguous component carriers and inter-band aggregation. This paper also presents the enhancement of LTE spectrum flexibility through carrier aggregation, further extension of multi-antenna transmission and provision of improvements in the area of inter-cell interference coordination in heterogeneous network deployments.

With respect to the carrier aggregation (CA) in
a LTE small cell access point system, the
performance of an independent and cross
component carrier (CC) scheduling is simulated
and analyzed in this paper. According to the
results, we obtained a capacity increase of
about 17~46% for the cross CC max rate (MR)
algorithm and about 12~45% for the cross CC
proportional fair (PF) algorithm. On the other
hand, in the round robin (RR) scenario, we
cannot notice the differences between the
independent CC and cross CC scheduling
policies on allocating resources. We also found
that CA frequency combination 1.8GHz CC +
800MHz CC has a better performance when
comparing to the other combinations with
respect to total average UE throughput.

This paper provides a view on the technologies being considered for Long Term Evolution-Advanced (LTE-Advanced). The evolution from third generation (3G) to fourth generation (4G) is described in terms of performance requirements and main characteristics. The main technologies for LTE-Advanced are explained, together with possible improvements, their associated challenges, and some approaches that have been considered to tackle those challenges. By the design and optimization of upcoming radio access techniques and a further evolution of the existing system, the Third Generation Partnership Project (3GPP) had laid down the foundations of the future Long Term Evolution (LTE) advanced standards the 3GPP candidate for 4G. The various technology components like wideband transmission and spectrum sharing, multi antenna solutions, coordinated multiple transmission/reception (CoMP) and relaying, introduced to meet the requirements for LTE Advanced systems, have been discussed.

To meet future demands on user experience and traffic volumes, mobile networks need to evolve towards providing higher capacities and data rates. In this paper we investigate the feasibility of incorporating higher frequency bands (15 GHz) and beamforming to support this evolution. We see that using user-specific beamforming, the challenging propagation conditions at higher frequencies are mitigated and outdoor-in coverage is often possible. In places where 15 GHz coverage is not satisfactory, swift fallback to a lower frequency band is essential. This is seamlessly provided by carrier aggregation with a 2.6 GHz band. Together these components provide a ten-fold increase in capacity over a reference system operating only at 2.6 GHz.

Carrier Aggregation (CA) is one of the Long Term Evolution Advanced (LTE-A) features that allow mobile network operators (MNO) to combine multiple component carriers (CCs) across the available spectrum to create a wider bandwidth channel for increasing the network data throughput and overall capacity. CA has a potential to enhance data rates and network performance in the downlink, uplink, or both, and it can support aggregation of frequency division duplexing (FDD) as well as time division duplexing (TDD). The technique enables the MNO to exploit fragmented spectrum allocations and can be utilized to aggregate licensed and unlicensed carrier spectrum as well. This paper analyzes the performance gains and complexity level that arises from the aggregation of three inter-band component carriers (3CC) as compared to the aggregation of 2CC using a Vienna LTE System Level simulator. The results show a considerable growth in the average cell throughput when 3CC aggregations are implemented over the 2CC aggregation, at the expense of reduction in the fairness index. The reduction in the fairness index implies that, the scheduler has an increased task in resource allocations due to the added component carrier. Compensating for such decrease in the fairness index could result into scheduler design complexity. The proposed scheme can be adopted in combining various component carriers, to increase the bandwidth and hence the data rates.

This deliverable is the final innovation report from the innovation workpackage in WINNER+. The document describes the latest innovations and their assessment as well as summarizes the innovations developed in the work package during the project. We analyze the suitability of these innovations as technology enablers for improving current systems, in particular IMT Advanced and beyond.

Carrier aggregation (CA) and spatial multiplexing (SM) multiple input multiple output (MIMO) antenna systems are used in the 4G and beyond wireless systems to achieve the desired data rates. This paper investigates the performance of the inter-band CA and SM MIMO in LTE-Advanced and recommends a CA scenario that leads to both efficient use of the MIMO antenna elements and balanced transmit power of the component carriers (CCs). The study is performed in an urban environment considering many eNodeB-UE links at CCs of 800 MHz and 2.6 GHz for different combinations of single and multiple-antenna systems. An urban site-specific 3D ray-tracing tool combined with measured antenna 3D radiation patterns is used to model radio channel of eNodeB-UE links. The simulation results show dependency of the aggregated throughput performance on the number of aggregated spatial streams and cell radius. For enhanced performance, this paper recommends aggregating either 4x4 SM MIMO operating at 800 MHz with 1x1 antenna system operating at 2.6 GHz for a cell radius of 450 m or, alternatively, 4x4 SM MIMO operating at 800 MHz with 2x2 SM MIMO operating at 2.6 GHz for a cell radius of 350 m.

Carrier aggregation and integration of heterogeneous networks allow the mobile user equipment to benefit from wider bandwidth and radio coverage of different access technologies. However, these technologies have increased handoff scenario probability through user equipment's mobility, leading to high outage probability and low throughput. Handover is an important aspect of mobility management which allows users to migrate from one cell to another without losing connections. But no lone access technology meets the requirements of providing seamless communication without loss and delay. Therefore, high-quality service continuity and reliable user equipment access to network anywhere and at any time require the design of an appropriate handover decision algorithm. In this paper, a multi-criteria based handover decision-making algorithm is proposed to evade loss of communication and provide better performance to the system. It adaptively makes handover decisions based on different decision criteria (load, availability of resources, and the handover scenario type) in addition to signal interference to noise ratio. The multi-criteria handover decision making algorithm-based method chooses among the cells that satisfy the requirements for the handover. As compared to some existing handover decision algorithms, simulation result shows that this algorithm improves system performance in terms of handover failure by 93%, 72%, and 58%; radio link failure reduction by 77%, 43%, and 22%; and handover ping-pong by 81%, 59%, and 36% over the conventional received signal strength, received wireless transmission line, and multi-influence factor hand over decisions respectively.

This paper presents the energy performance of a new radio access technology (RAT) component in 5G, here denoted as 5G-NX. The 5G-NX RAT encompasses massive beamforming and an ultra-lean design as two of its key technology components. The user throughput, resource utilization of the cells and daily average area power consumption are evaluated by means of system level simulations in an Asian city scenario, and the results are compared with a traditional LTE deployment using the same network layout. The simulation results indicate that the  new 5G-NX system provides much better energy performance compared to LTE and this is primarily due to the ultra-lean design and the high beamforming gain that provides both longer and more efficient component sleep in the network. At expected traffic levels beyond 2020, 5G-NX is shown to decrease the network energy consumption by more than 50% while providing around 10 times more capacity.