HetNet Deployment Research Articles

Maximizing energy efficiency in HetNets through centralized and distributed sleep strategies under QoS constraint

This research addresses the critical need to optimize the Energy Efficiency (EE) for Ultra-Dense HetNets amid the ever-increasing demands for high-speed data networks. The rapid increase in high-speed devices highlights the urgent necessity for a transformative change in upcoming 5G cellular networks. According to Ericsson's 2022 report, mobile data traffic volume is expected to double by 2027, with mobile video traffic anticipated to rise by nearly 30% each year. In response to these challenges, researchers have identified essential technologies that facilitate 5G networks, including massive Multiple-input-Multiple-output (m-MIMO) systems and HetNets. Although both promise enhanced coverage and throughput, HetNets emerges as a cost-effective solution, surpassing m-MIMO in implementation cost and coverage. However, achieving maximum EE in HetNets necessitates careful consideration of various constraints, including delay, coverage probability, and Signal-to-Interference-plus-Noise Ratio (SINR) thresholds. This research marks a significant milestone in adopting the Distributed Dynamic Opportunistic Sleep Strategy (D-DOSS) approach. The D-DOSS method organizes small clusters throughout the network and evaluates key Quality of Service (QoS) parameters including Energy Utilization Efficiency (EUE), Coverage Probability, Data Throughput, and Success Probability using Monte Carlo simulations. This research analyzes Distributed Sleep (DS) and Centralized Schemes (CS) concerning given QoS parameters. While DS methodologies often exhibit performance trade-offs compared to CS, they provide significant advantages in terms of ease of implementation and management. CS, though representing the most commonly used method in ultra-dense HetNets involves high computational costs that complicate its management. By integrating the D-DOSS and addressing various constraints, this research not only advances HetNet technologies but also makes a significant contribution to optimizing EE while preserving network performance and QoS. The innovative D-DOSS approach offers a promising solution to the challenges of energy efficiency in wireless communication networks and paves the way for future advancements in HetNet deployments. The results and analysis show that D-DOSS effectively addresses the limitations of DS and outperforms existing CS techniques.

3D Boundary Modeling and Handover Analysis of Aerial Users in Heterogeneous Networks

Aerial user equipments (AUEs) levitating in the air are growingly used in various applications for the agility, but leads to link fluctuation and deterioration of handover (HO) performance, which is marked in heterogeneous networks (HetNets). However, existing HO models have not investigated HO performance of cellular-connected unmanned aerial vehicles (UAVs) under the influence of shadow fading at different altitudes. This paper proposes a 3D boundary model derived by trigger conditions to analyze HO performance of aerial users considering the shadow fading effect in two-tier HetNets, where the 3D HO trigger boundary and handover failure (HF) boundary are both in the form of a hemispherical shell with typical small base station (SBS) as center, composed of the point sets corresponding to the above HO events, which are derived by the Received Signal Strength (RSS) ratio of target SBS to source macro base station (MBS). Especially, the calculation of HO events probabilities under trigger conditions are transformed to the relationship between time-to-trigger (TTT) and during time inside 3D boundary by exploring the positional relationship between straight line and hemispherical shell boundaries. Thus, the compact expressions of HO probability, HF probability and PP probability are obtained to quantify the effect of 3D mobility and HO parameters in various deployment of HetNets. Theoretical results show that HF and PP probability dramatically drop by 68.5% and 47.1% when <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H=20$</tex-math></inline-formula> m comparing to scenario of terrestrial users and HetNets deployment should be considered when choosing appropriate HO parameters.

Graph neural network-based cell switching for energy optimization in ultra-dense heterogeneous networks

The development of ultra-dense heterogeneous networks (HetNets) will cause a significant rise in energy consumption with large-scale base station (BS) deployments, requiring cellular networks to be more energy efficient to reduce operational expense and promote sustainability. Cell switching is an effective method to achieve the energy efficiency goals, but traditional heuristic cell switching algorithms are computationally demanding with limited generalization abilities for ultra-dense HetNet applications, motivating the usage of machine learning techniques for adaptive cell switching. Graph neural networks (GNNs) are powerful deep learning models with strong generalization abilities but receive little attention for cell switching. This paper proposes a GNN-based cell switching solution (GBCSS) that has a smaller computational complexity than existing heuristic algorithms. The presented performance evaluation uses the Milan telecommunication dataset based on real-world call detail records, comparing GBCSS with a traditional exhaustive search (ES) algorithm, a state-of-the-art learning-based algorithm, and the baseline without cell switching. Results indicate that GBCSS achieves a 10.41% energy efficiency gain when compared with the baseline and achieves 75.76% of the optimal performance obtained with ES algorithm. The results also demonstrate GBCSS’ significant scalability and generalization abilities to differing load conditions and the number of BSs, suggesting this approach is well-suited to ultra-dense HetNet deployment.

QoS-based Packet Scheduling Algorithms for Heterogeneous LTE-Advanced Networks: Concepts and a Literature Survey

The number of LTE (Long-Term Evolution) users and their applications has increased significantly in the last decade, which increased the demand on the mobile network. LTE-Advanced (LTE-A) comes with many features that can support this increasing demand. LTE-A supports Heterogeneous Networks (HetNets) deployment, in which it consists of a mix of macro-cells, remote radio heads, and low power nodes such as Pico-cells, and Femto-cells. Embedding this mix of base-stations in a macro-cellular network allows for achieving significant gains in coverage, throughput and system capacity compared to the use of macrocells only. These base-stations can operate on the same wireless channel as the macro-cellular network, which will provide higher spatial reuse via cell splitting. Also, it allows network operators to support higher data traffic by offloading it to smaller cells, such as Femto-cells. Hence, it enables network operators to provide their growing number of users with the required Quality of Service (QoS) that meets with their service demands. In-order for the network operators to make the best out of the heterogeneous LTE-A network, they need to use QoS-based packet scheduling algorithms that can efficiently manage the spectrum resources in the HetNets deployment. In this paper, we survey Quality of Service (QoS) based packet scheduling algorithms that were proposed in the literature for the use of packet scheduling in Heterogeneous LTE-A Networks. We start by explaining the concepts of QoS in LTE, heterogeneous LTE-A networks, and how traffic is classified within a packet scheduling architecture for heterogeneous LTE-A networks. Then, by summarising the proposed QoS-based packet scheduling algorithms in the literature for Heterogeneous LTE-A Networks, and for Femtocells LTE-A Networks. And finally, we provide some concluding remarks in the last section.

Optimization of Pico-eNB Tx Power and the Effects of Picocell Range Expansion in Multiband HetNet

The use of heterogeneous networks (HetNets) that combine macrocells and picocells in the same coverage is effective in increasing system capacity and improving user throughput. The use of high carrier frequency bands is also expected to help achieving higher data rates because it promises vast amounts of signal bandwidth. Therefore, multiband HetNets with picocells operating at high carrier frequency bands have attracted significant attention with the aim of increasing system capacity and achieving a high user throughput in fifth-generation mobile systems and beyond. In HetNet deployments, a picocell range expansion (CRE) technique that virtually expands the picocell coverage is well known to allow more user equipment (UE) to access the picocell providing a fixed cell selection offset (CSO) for all UE. Thus far, there has not been sufficient research on optimizing the transmission (Tx) power of pico-evolved node Bs (eNBs) operating at high carrier frequency bands in multiband HetNets. In addition, the effects of CRE in multiband HetNets have not been clarified. In this paper, we first investigated the optimal Tx power of pico-eNB in a multiband HetNet combining macrocells operating at 2 GHz and picocells operating at 4.5 GHz band with a wider signal bandwidth using system-level computer simulations. Then, from the user throughput perspective, we investigated the effects of CRE providing a positive CSO for UE using two pico-eNB Tx powers close to the optimal value. Using these results, we discussed how to choose the pico-eNB Tx power when CRE was activated and validated the design method for a multiband HetNet.

Heterogeneous network spectrum allocation scheme based on three-phase bargaining game

The fifth generation (5G) networks are envisioned to support the exploding mobile data traffic demands while improving quality of service (QoS) provision. The heterogeneous network (HetNet) platform provides one possible solution for dealing with this traffic explosion problem. However, several technical issues and challenges are associated with the deployment of HetNets. In this paper, we aim to design a new spectrum allocation scheme to effectively use the limited HetNet spectrum resource. By employing the main ideas of relative utilitarian, equality averse and inequality averse bargaining solutions, our approach unfolds into three stages of spectrum allocation process while balancing the efficiency and fairness. Based on the main features of each bargaining solution, we hierarchically apply these three solutions to spectrum assignment among BSs, spectrum allocation among SBSs, and spectrum sharing among applications, respectively. According to the advantages of cooperative bargaining approach, the proposed scheme takes various benefits in a rational way. The numerical simulations demonstrate the effectiveness and potential gain of our proposed three-phase spectrum allocation mechanism over the existing protocols.

Analysis of Acquired Indoor LTE-A Data from an Actual HetNet Cellular Deployment

Increasing the user downlink throughput is always a task of utmost importance for any cellular network service provider. However, most of the research is only focused on system simulations due to environmental simplicity. In this paper, instead of focusing on theoretical simulations, we aim to find the best practical solution to increase user throughput in an actual HetNet deployment where many small cells are deployed inside a building. An inter-frequency deployment is implemented in the actual LTE-A HetNet environment. A series of data collections were conducted in an actual indoor LTE-Advanced HetNet (heterogeneous network) environment with optimization strategies such as ABS (Almost Blank Subframe) and turning off/on interfering antennas. Detailed findings and analysis are provided to better understand the complicated actual HetNet environment. This work is also important to understand the future 5G network since the small cells and HetNet will continue to play an important role in the 5G network.

QoE-Aware Resource Allocation for Profit Maximization Under User Satisfaction Guarantees in HetNets With Differentiated Services

The rise of third-party content providers and the introduction of numerous applications have been driving the growth of mobile data traffic in the past few years. The applications’ various quality of service requirements as well as the use of multiple devices per user have increased the traffic heterogeneity, pressing the telecommunications industry to the deployment of dense heterogeneous networks (HetNets). At the same time, the rise of the content providers has also led to the decrease of the mobile network operators’ (MNOs) revenues. Under these circumstances, the MNOs need to guarantee the users’ quality of experience (QoE) requirements, while ensuring the sustainability of HetNet investments. To this end, we consider a HetNet deployment where MNOs offer a multitude of services with diverse pricing. We propose a heuristic, greedy, and QoE-aware resource allocation algorithm with fairness and overall user satisfaction constraints to maximize the MNO profit, while providing high QoE. Simulation results show that the proposed algorithm can handle traffic heterogeneity by achieving substantial profit and QoE gains, compared to state-of-the-art algorithms.

Maximum Transmit Power for UE in an LTE Small Cell Uplink

To furnish the network with small cells, it is vital to consider parameters like cell size, interference in the network, and deployment strategies to maximize the network’s performance gains expected from small cells. With a small cell network, it is critical to analyze the impact of the uplink power control parameters on the network’s performance. In particular, the maximum transmit power (Pmax) for user equipment (UE) needs to be revisited for small cells, since it is a major contributor towards interference. In this work, the network performance was evaluated for different Pmax values for the small cell uplink. Various deployment scenarios for furnishing the existing macro layer in LTE networks with small cells were considered. The Pmax limit for a small cell uplink was evaluated for both homogenous small cell and heterogeneous networks (HetNet). The numerical results showed that it would be appropriate to adopt Pmax = 18 dBm in uniformly distributed small cells rather than Pmax = 23 dBm, as in macro environments. The choice of Pmax = 18 dBm was further validated for three HetNet deployment scenarios. A decrease of 0.52 dBm and an increase of 0.03 dBm and 3.29 dBm in the proposed Pmax = 18 dBm were observed for the three HetNet deployments, respectively. Furthermore, we propose that the fractional power control mode can be employed instead of the full compensation mode in small cell uplinks.

Joint Optimization of Interference Coordination Parameters and Base-Station Density for Energy-Efficient Heterogeneous Networks.

Heterogeneous networks (HetNets), consisting of macro-cells and overlaying pico-cells, have been recognized as a promising paradigm to support the exponential growth of data traffic demands and high network energy efficiency (EE). However, for two-tier heterogeneous architecture deployment of HetNets, the inter-tier interference will be challenging. Time domain further-enhanced inter-cell interference coordination (FeICIC) proposed in 3GPP Release-11 becomes necessary to mitigate the inter-tier interference by applying low power almost blank subframe (ABS) scheme. Therefore, for HetNets deployment in reality, the pico-cell range expansion (CRE) bias, the power of ABS and the density of pico base stations (PBSs) are three important factors for the network EE improvement. Aiming to improve the network EE, the above three factors are jointly considered in this paper. In particular, we first derive the closed-form expression of the network EE as a function of pico CRE bias, power reduction factor of low power ABS and PBS density based on stochastic geometry model. Then, the approximate relationship between pico CRE bias and power reduction factor is deduced, followed by a linear search algorithm to get the near-optimal pico CRE bias and power reduction factor together at a given PBS density. Next, a linear search algorithm is further proposed to optimize PBS density based on fixed pico CRE bias and power reduction factor. Due to the fact that the above pico CRE bias and power reduction factor optimization and PBS density optimization are optimized separately, a heuristic algorithm is further proposed to optimize pico CRE bias, power reduction factor and PBS density jointly to achieve global network EE maximization. Numerical simulation results show that our proposed heuristic algorithm can significantly enhance the network EE while incurring low computational complexity.

Leveraging Intelligence from Network CDR Data for Interference Aware Energy Consumption Minimization

Cell densification is being perceived as the panacea for the imminent capacity crunch. However, high aggregated energy consumption and increased inter-cell interference (ICI) caused by densification, remain the two long-standing problems. We propose a novel network orchestration solution for simultaneously minimizing energy consumption and ICI in ultra-dense 5G networks. The proposed solution builds on a big data analysis of over 10 million CDRs from a real network that shows there exists strong spatio-temporal predictability in real network traffic patterns. Leveraging this, we develop a novel scheme to pro-actively schedule radio resources and small cell sleep cycles yielding substantial energy savings and reduced ICI, without compromising the users QoS. This scheme is derived by formulating a joint Energy Consumption and ICI minimization problem and solving it through a combination of linear binary integer programming, and progressive analysis based heuristic algorithm. Evaluations using: 1) a HetNet deployment designed for Milan city where big data analytics are used on real CDRs data from the Telecom Italia network to model traffic patterns, 2) NS-3 based Monte-Carlo simulations with synthetic Poisson traffic show that, compared to full frequency reuse and always on approach, in best case, the proposed scheme can reduce energy consumption in HetNets to 1/8th while providing same or better QoS.

3GPP-Inspired HetNet Model Using Poisson Cluster Process: Sum-Product Functionals and Downlink Coverage

The growing complexity of heterogeneous cellular networks (HetNets) has necessitated a variety of user and base station (BS) configurations to be considered for realistic performance evaluation and system design. This is directly reflected in the HetNet simulation models proposed by standardization bodies, such as the 3rd Generation Partnership Project (3GPP). Complementary to these simulation models, stochastic geometry-based approach, modeling the locations of the users, and the $K$ tiers of BSs as independent and homogeneous Poisson point processes (PPPs), has gained prominence in the past few years. Despite its success in revealing useful insights, this PPP-based $K$ -tier HetNet model is not rich enough to capture spatial coupling between user and BS locations that exists in real-world HetNet deployments and is included in 3GPP simulation models. In this paper, we demonstrate that modeling a fraction of users and arbitrary number of BS tiers alternatively with a Poisson cluster process (PCP) captures the aforementioned coupling, thus bridging the gap between the 3GPP simulation models and the PPP-based analytic model for HetNets. We further show that the downlink coverage probability of a typical user under maximum signal-to-interference-ratio ( $ \mathtt {SIR}$ ) association can be expressed in terms of the sum-product functionals over PPP, PCP, and its associated offspring point process, which are all characterized as a part of our analysis. We also show that the proposed model converges to the PPP-based HetNet model as the cluster size of the PCPs tends to infinity. Finally, we specialize our analysis based on general PCPs for Thomas and Matern cluster processes. Special instances of the proposed model closely resemble the different configurations for BS and user locations considered in 3GPP simulations.

Joint ABS and user grouping allocation for HetNet with picocell deployment in downlink

In order to resolve the co-channel inter-cell interference problem in heterogeneous networks (HetNet), the feature of almost blank subframes (ABS) in the time domain of the enhanced inter-cell interference coordination (eICIC) is utilized. In this paper, an ABS configuration design is developed on downlink in HetNet and the associated resource allocation problem for maximizing the system performance with fairness among user equipments (UEs) is considered. Compared to conventional problems, the resource assignment problems include the configuration of ABS pattern and the resource allocation for macro UEs and pico UEs, which aims to maximize the downlink throughput and balance the traffic offloading in intra-frequency HetNet deployments. First, this paper introduces an ABS pattern design by using the channel condition, which is developed in terms of the time domain resource. Subframes are categorized as protected or normal subframes for reducing interference impact to pico UEs. Based on the configuration of the ABS pattern, we develop a grouping strategy to determine which pico UEs use either protected or normal subframes. Besides, the assignment of resource blocks with respect to the resource in the frequency domain is developed along with the fairness among UEs. The proposed joint allocation scheme takes the system throughput and the fairness into account, and has better performance than the existing schemes. Simulation results also reveal that the performance of the proposed joint allocation scheme approximates the optimal solution with the full search scheme.

A Techno-Economic Framework for 5G Transport Networks

Wireless heterogeneous networks (HetNets) are a cost- and energy-efficient alternative to provide high capacity to end users in the future 5G communication systems. However, the transport segment of a RAN poses a big challenge in terms of cost and energy consumption. In fact, if not planned properly, its resulting high cost might limit the benefits of using small cells and impact the revenues of mobile network operators. Therefore, it is essential to be able to properly assess the economic viability of different transport technologies as well as their impact on the cost and profitability of a HetNet deployment (i.e., RAN plus transport). This article first presents a general and comprehensive techno-economic framework able to assess not only the TCO but also the business viability of a HetNet deployment. The framework is then applied to the specific case study of a backhaul-based transport segment. In the evaluation work two technology options for the transport network are considered (i.e., microwave and fiber) assuming both a homogeneous (i.e., macrocells only) and a HetNet deployment. Our results demonstrate the importance of selecting the right technology and deployment strategy in order not to impact the economic benefits of a HetNet deployment. Moreover, the results also reveal that a deployment solution with the lowest TCO does not always lead to the highest profit.

Stochastic Geometry Based Framework for Coverage and Rate in Heterogeneous Networks with Sectored Fractional Frequency Reuse

Modern day cellular networks are driven by the need to provide ubiquitous connectivity with very high spectral efficiency to both indoor and outdoor users, hence the need to deploy small cells over conventional macrocells in a Heterogeneous Network (Hetnet) deployment. To alleviate the resulting inter-cell and cross-tier interference, effective inter-cell interference coordination (ICIC) schemes such as Fractional Frequency Reuse (FFR) are employed, and have been widely studied in perfect geometry network scenarios which are too idealistic and not easily adaptable to the complexity of Hetnets. This work provides an analytical framework for the performance of such FFR schemes in Hetnets with antenna sectorization employed at the macro tier, by leveraging stochastic geometry tools to model base station locations of both macro and femto tiers using the Poisson Point Process (PPP). We study the effects of varying system parameters and consider cross-tier femto interference commonly ignored in many analytical works in literature. Furthermore, the femtocells employ a sensing algorithm to minimize spectrum sharing with macro users in close proximity, especially at the transition areas of center and edge region where cross-tier interference could be monumental. Numerical simulations are used to evaluate performance of the proposed framework in terms of coverage probability and average user rate, and results are compared with traditional FFR schemes and the No-FFR deployment. To the best of the author’s knowledge, this is the first analytical framework characterizing sectored-FFR schemes using stochastic geometry tools in Hetnets.

Feasibility of Green Network Deployment for Heterogeneous Networks

Green technology is a new term which is used to describe the energy efficient technologies. In the context of mobile communications industry, complying with the green technology strategy is a challenge. This is because of the tradeoff between the Quality of Service (QoS) provided and the total energy used in the transmission. Reducing the transmission energy may cause degradation in the QoS, more distinctively, in highly populated areas. This paper explores the possibility of achieving the green technology goal in planning and deployment of the HetNet mobile network with efficient network QoS. A decoupled two stage multi-objective genetic algorithm is developed to provide the network base station distribution that would satisfy both the network QoS and green network demands. In the first stage the algorithm estimates the base station parameters for more energy efficient HetNet deployment for optimum network coverage. The initial base station candidate locations are provided by a network operator in Kuala Lumpu, Malaysia. The second stage of the developed algorithm selects the number and location of RS associated with each base station optimized in the first stage to improve the network capacity. To optimize the network power, a novel arrival rate based HetNet total power consumption model is derived to investigate the parameters that affect the network power expenditure. Results show that a remarkable energy saving of about 40 % of the operator transmission power could be achieved with full network coverage. The addition of RS associated with each base station would greatly improve network capacity on the expense of its power expenditure. The relative RS to base station capacity plays major rule in reducing HetNet power expenditure.

Downlink SINR and rate distribution of ultra-dense HetNets with burst traffic

SINR distribution and rate overage distribution are crucial for optimization of deployment of Ultra-dense HetNets. Most existing literatures assume that BSs have full queues and full-buffer traffic. In fact, due to ultra-dense deployment of small cells, traffic in small cell varies dramatically in time and space domains. Hence, it is more practical to investigate scenario with burst traffic. In this paper, we consider a two-tier non-uniform ultra-dense HetNet with burst traffic, where macro BSs are located according to Poisson Point Process (PPP), and pico BSs are located according to Poisson Hole Process (PHP). The closed-form expressions of SINR distribution and rate distribution are derived, and then validated through simulation. Our study shows that different from the result of full buffer case, the SINR distribution and rate distribution of users depend on the average transmission probabilities of BSs in burst traffic case.

Spectrum management issues for heterogeneous networks in commons spectrum

Purpose The purpose of this paper is to analyse some of the spectrum management policy implications of an evolving set of wireless technologies. Specially, deployment of heterogeneous networks (HetNets) as part of the rollout of long-term evolution networks and their expected use as the heart of next-generation services raises the question as to whether such networks should lead to any spectrum management policy changes. Design/methodology/approach The paper describes the use and variety of HetNets when using licensed and unlicensed or commons spectrum. Findings The paper demonstrates that there is little need to change current spectrum licensing regimes to deal with these networks in a licensed spectrum. However, it also shows that the deployment of HetNets other than WiFi in an unlicensed spectrum creates an information asymmetry, which means that spectrum regulators will find assessment of spectrum demand more difficult. The paper also highlights the problem facing spectrum regulators when there is a potential for interference to unlicensed services which are widely deployed but have no right to protection from interference. Practical implications Spectrum regulators will need to understand the extent to which an unlicensed spectrum is being used by mobile network operators to deliver wireless broadband services. This understanding is needed to be able to address potential interference with other services using an unlicensed spectrum and to be able to forecast spectrum demand. Originality/value The development of technologies that are designed to be used by existing mobile network operators for the delivery of wireless broadband services using an unlicensed spectrum creates novel regulatory challenges. This paper reviews some of these.

A Flexible and Cost-Effective Heterogeneous Network Deployment Scheme for Beyond 4G

The network capacity has to be maximized to support the ever-increasing data traffic demand. One of the potential outcomes to enhance the network capacity is to enhance the spectral efficiency per unit area by expanding the serving node densities. This is unreasonable on account of present Macro evolved node B (eNB) for which site acquisition is expensive. The idea of heterogeneous network (HetNet) and multi-hop relay (MHR) are extremely prominent in long-term evolution (LTE) standard, where small cells are deployed along with Macro cell. Small cells are more suitable solution for the coverage and traffic issues experienced by Macro cell users. Unfortunately, HetNet deployment is not specified in any of the standards. The network operators have been managing tremendous investments for cellular infrastructures. Because of the high cost and lack of radio resources, a precise and productive HetNet deployment seems uttermost important. In this work, a flexible four-stage fuzzy logic-based HetNet deployment scheme is proposed, which deploys mix of Macro-eNB, Micro-eNB and relay station (RS) by considering capacity, coverage and cost factors. The proposed scheme identifies the required number of eNBs, their types and deployment locations to offer the expected coverage in a cost-effective way. The simulation results demonstrate that our proposed scheme is more flexible and offers improved performance in terms of system cost and power ratio than the conventional HetNet deployment schemes.

Survey on Algorithms and Strategies for Mobility Enhancement under Heterogeneous Network (HetNet) Deployment Circumstances

Cell selection/reselection and handover (HO) are important mobility features and challenges of wireless cellular system. When network topology transforms from macro-only to heterogeneous network (HetNet) deployment, the imbalance of transmitted power and coverage area of different kinds of cells in HetNet introduce more challenges to those two important processes. In this paper, we investigate and elaborate some new algorithms and strategies to meet those challenges. On cell selection/reselection, there are two directions in associating more UEs with small cells, one is RSRP-based by introducing a empirical bias to expand small cells’ coverage area, the other is fairness-based to maximize the system throughput and usage of resources. As to more important and difficult HO process, the proposed methods include optimizing the parameters of event A3, handling time to trigger(TTT), optimizing HO process and utilizing inter-cell interference coordination algorithm(ICIC) etc, to maximize the usage of capability of deployed small cell. The presented new algorithms and strategies promise specific performance improvement with introducing receivable time and computing complexity.