FEMTOCELL technology was emerged to solve the problem of growing demands for high data rates in cellular communications networks. It improves the indoor coverage and provides more spatial reuse and higher-quality links for users in a cost effective manner and at the same time, enhance the network capacity. Despite all potential benefits of FEMTOCELLs, there are some important issues (e. g., the interference and the outage probability) that should be addressed before their deployment. The main goal of this paper is to improve the user performance in FEMTOCELL networks using the ultra-wideband (UWB) technology as an effective way to reduce the interference. In this technology, transmitters use a low power signals in a very wide band and work without any harsh effects on adjacent communication systems. (The systems based on this technology create the least interference on narrow band systems which are located in their neighbor. ) Considering FEMTOCELLs enabled with the UWB technology, femto users can operate without any significant interference on macro users. To study the efficiency of this network, we assume that macrocell and FEMTOCELL users are distributed according to the Poisson point process in the network. We calculate the outage probability of macro users which receive the UWB interference signal from the neighbor femto access points along with the outage probability of femto users which receive the narrow band signal of macro base station as the interference. Simulation results indicate that applying the UWB technology in FEMTOCELL networks effectively improve the outage probability of users.

In order to increase throughput and spectral efficiency in a heterogeneous network including a macro and a FEMTOCELL, we propose a combined offloading with In-Band Full Duplex (IBFD) scheme in this paper. Traffic offloading to the FEMTOCELL is deployed to transmit network users traffic to a macrocell base station in the uplink. In other words, all or a part of the traffic is offloaded to the FEMTOCELL and then transmitted to the macrocell, while the rest of traffic is transmitted to the macrocell directly. In the FEMTOCELL, we deploy and investigate IBFD technology, i.e., simultaneous transmit and receive traffic in one frequency band. Furthermore, in order to improve throughput of the network, we propose several scheduling schemes to transmit traffic. Finally, optimal number and position of users who use IBFD or do not use it, are determined. We propose a heuristic solution to find optimal position of IBFD users. Simulation results verify the network throughput improvement and power consumption reduction.

Available techniques in handover management in cellular communication networks can’t keep unnecessary events and delay decision at a low level state. The main purpose of this paper is to provide the intelligence method which is able to minimize the number of unnecessary events and allowing the necessary requests to occur and so improves the overall network performance. In order to achieve such a goal, in the proposed method, we have used the geographical knowledge from building maps with spectral clustering in the area covered by FEMTOCELL. Therefore, we require to develop the spectral clustering based on geographical information. The experimental results on real dataset and performed simulations indicate that the superiority of the proposed method in allocating the user to appropriate cell and acceptable ability to manage the handover in heterogeneous layer of FEMTOCELL-macrocell.

Resource allocation has always been one of the main challenges in the design of wireless cellular networks. Suitable resource allocation, more specifically that includes suitable base station selection and bandwidth allocation can play an effective role in interference mitigation and users’ quality of service requirement satisfaction. In this paper, a game theoretic approach is proposed to solve the BS selection problem in two-tier wireless FEMTOCELL networks. We formulate the competitive behavior of users as evolutionary game theory. We calculate the probability of a user choosing a BS, compute the cell load of each BS, and analyze the demand rejection probability of the user associated with the BS. The proposed approach maximizes network throughput as well as meeting the QoS requirements of the users. Finally, we propose a decentralized learning algorithm based on EXP3 algorithm to achieve the evolutionary equilibrium as the solution of the game. Simulation results show that the proposed approach achieves a desirable performance and guarantees users’ QoS requirements.

FEMTOCELLs are widely used to improve poor indoor coverage and decrease the cellular networks high cost. The fact that FEMTOCELLs and macrocells share similar frequency bands leads to a major challenge in time/frequency resources allocation. Addressing fairness among FEMTOCELLs and improving time/frequency resources utilization are the main objectives of the previous studies. The balance between FEMTOCELL level fairness and utilization is considered in some of the previous studies. Providing user level fairness with respect to User Equipments (UEs) demands is the issue that has not received adequate attention so far.Here, a centralized resource allocation algorithm is proposed to improve the balance between user level fairness and radio resource utilization where the demand of UEs for radio resources are involved. In this algorithm, two independent phases are followed. The first phase assigns resources to FEMTOCELLs in a greedy manner to increase the reused spectrum utilization based on the proposed priority. The second phase is planned in a manner to guarantee the fairness between UEs by considering their required resources whenever the residual resources are not proportional to the unmet requirements. Compared to the conventional methods, this proposed approach leads to an improvement in terms of utilization, fairness, and average amount of satisfied demands.

As one of the promising approaches to increase the network capacity, Full-duplex (FD) communications have recently gained a remarkable attention. FD communication enables wireless nodes to simultaneously send and receive data through the same frequency band. Thanks to the recent achievements in the self-interference (SI) cancellation, this type of communication is expected to be potentially utilized in cellular systems, especially in small cell networks. In this paper, we integrate the FD communications into FEMTOCELL networks where FEMTOCELL users (FUs) share the same spectrum with macro users (MUs). In particular, aiming to maximize the number of admitted FUs in the network and satisfying the target rate for FUs, we jointly study the problem of sub-channel allocation, duplexing-mode selection, and power control for FUs in both uplink (UL) and downlink (DL) transmissions. Moreover, we address the power control problem for macro-tier where the main goal is to minimize the transmission power of prioritized MUs while guaranteeing a target rate for them. To jointly address these problems for both tiers, we propose a distributed algorithm in which FBSs and admitted FUs choose whether to operate in half-duplex (HD) or FD mode so as to meet their target rate. The convergence and performance of the proposed algorithm are evaluated through simulation where it is demonstrated that the average admission ratio of FUs in our proposed distributed scheme surpasses the existing traditional HD approaches.

Heterogeneous networks, including macrocell and FEMTOCELL, cause to increase network capacity. Also, they improve quality of offers services to users in cellular networks. Common subchannel allocation among different tier users, make cross-tier interference among users. Since macrocell users have priority to FEMTOCELL ones, presence of FEMTOCELL users should not prevent macrocell users to access minimum quality-of-service. In this paper, a power control and subchannel allocation scheme in downlink transmission an orthogonal frequency division multiple access (OFDMA) based two tier of macrocell and FEMTOCELL is proposed, aiming the maximization of FEMTOCELL users total data rate, in which the minimum QOS for all macrocell users and FEMTOCELL delay-sensitive users is observed. In macrocell tier, two different problems are considered. The first problem aim to maximizing the total threshold of tolerable cross-tier interference for macrocell users and the second problem’s goal is minimizing the macrocell’s total transmission power. For the FEMTOCELL tier, maximizing the users total data rate is the objective. Hungrian method, an assignment optimization method, is used for solving the first problem in macrocell tier. Moreover, in order to solve the second problem a heuristic method for subchannel allocation is proposed and dual Lagrange method is used for power control. In addition, in order to solve the problem for FEMTOCELL tier, a heuristic method is used for subchannel allocation. Subsequently, a dual Lagrange method which is one of the convex optimization problem solver is used, so that we can control the power. Finally, an extend simulations are performed to validate the performance of the proposed method.

The growth of the Internet of Things and mobile devices highly rely on independent and distributed operation in wireless networks. A focus on the allocation of spectrum for effective communication, mitigation of interference and reduction in the energy consumption in the wireless environment is essential. Non-availability of the spectrum in a wireless network can be overcome by spectrum reuse in Cognitive Radio FEMTOCELL networks (CRFN) which improves the indoor communication coverage. is mostly preferred. The spectrum is sensed at regular intervals by the secondary user (SU) to detect the presence of the primary user(PU). Sensing the spectrum reduces the performance and the throughput of the secondary users. To overcome the above in this research, a novel multichannel spectrum allocation (MSA) technique combined with a decode-and-forward (DF) based cooperative spectrum sensing scheme is proposed.  The information rate that can be transmitted over a given bandwidth is greatly enhanced in the proposed multichannel resource allocation (MRA) technique It is evident from the simulation results, that the throughput of the SUs is boosted when compared over the established techniques.