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Penetration of multimedia communications with mobile Wi-Fi and tethering requires wireless LANs (WLANs) to guarantee a specific bandwidth in densely deployed WLANs. IEEE802.11e (HCCA) with 802.11aa could use inefficiently radio frequency as well as fail to provide each WLAN with enough CFP period in which sending opportunity of a terminal is guaranteed. To guarantee a specific bandwidth even in densely...
Cloud-based Radio Access Network (C-RAN) is a promising architecture for future cellular networks, in which Baseband Units (BBUs) are placed at a centralized location, with capacity-constrained fronthaul connected to multiple distributed Remote Radio Heads (RRHs) that are far away from the BBUs. The centralization of signal processing enables the flexibility for coordinated multi-point transmission...
This paper considers the optimal energy efficient association for HetNets by applying almost blank subframes (ABSs) techniques. Aiming at maximizing energy efficiency (EE) without the quality of service (QoS) constraints, we obtain a closed-form optimal solution, which indicates that the optimal choice of blank resource block (RB) fraction for EE maximization is binary without individual user QoS...
In this paper, the quantity of interference on the primary user (PU) caused by the secondary user (SU) is investigated. An underlay spectrum sharing network is considered, where the different scenario of PU activity is modeled based on the duty cycle of PU channel. PU channel is classified into several activities according to the application of primary services. The interference to PU is observed...
The increasing demand for data and multimedia services, as well as the ubiquitous nature of the current generation of mobile devices have resulted in continuous network upgrades to support an ever-increasing number of users. However, given that wireless communication systems operate on radiofrequency waves, the health effects of electromagnetic (EM) emission from these systems are increasingly becoming...
This paper studies the resource allocation for multi-D2D (Device-to-Device) communications in heterogeneous networks with quality-of-service (QoS) guarantees for both cellular and D2D links. To improve the achievable rate of D2D communication and the spectrum utilization, one D2D pair is allowed to reuse multiple cellular spectrum resources. However, this scheme introduces more interference so that...
To achieve higher spectral efficiency in future wireless networks, small cells have been conceived to be deployed over conventional macrocell networks, generating heterogeneous networks (HetNets). However, interference between different tiers of HetNets is the main bottleneck for high spectral efficiency. Spectrum access, including spectrum deployment and channel access, is one of the most powerful...
In this paper, we define a collision area in a heterogeneous cellular network for the purpose of interference management between Device-to-Device (D2D) and conventional cellular (CC) communications. Currently, most D2D routing algorithms assume synchronized accurate location knowledge among users and the base stations. In reality, this level of location accuracy is difficult and power consuming in...
In smart cities, cellular network plays a crucial role to support connectivity anywhere and anytime. However, the communication demand brought by applications and services is hard to predict. Traffic in cellular networks might fluctuate heavily over time to time, which causes burden and waste under different traffic states. Recently, small cell was proposed to enhance spectrum efficiency and energy...
We have proposed a concept of a new Quality of Experience (QoE) oriented wireless local area network (WLAN) on which many applications can run with sufficient quality even in congested environment. The proposed system is designed by taking users’ QoE as a key metric. In this paper, we propose a practical functional flow featuring a new channel access control scheme based on loadable capacity prediction...
Large scale growth of wireless networks and the scarcity of the electromagnetic spectrum are imposing more interference to the wireless terminals which jeopardize the Quality of Service offered to the end users. In order to address this kind of performance degradation, this paper proposes a novel experimentally verified cognitive decision engine which aims at optimizing the throughput of IEEE 802...
This paper presents a generic approach for dimensioning LTE/LTE-A cellular networks. Dimensioning is the first step of cellular network planning that determines the approximate number of base stations (BSs) needed to cover a certain area. The proposed approach takes into account user density, service subscriptions, resource allocation, and interference mitigation. It can be implemented in heterogeneous...
In this paper, the optimization of base station (BS) deployment is investigated. After determining an approximate number of required BSs to cover an area of interest, the positions of these BSs are determined using the simulated annealing (SA) algorithm. Deployment using SA is compared to a benchmark approach consisting of a uniform deployment of the BSs over the area of interest. Scenarios with uniform...
With increasing number of autonomous heterogeneous devices in future mobile networks, an efficient resource allocation scheme is required to maximize network throughput and achieve higher spectral efficiency. In this paper, performance of network-integrated device-to-device (D2D) communication is investigated where D2D traffic is carried through relay nodes. An optimization problem is formulated for...
Device-to-device (D2D) underlaying communication brings great benefits to the cellular networks from the improvement of coverage and spectral efficiency at the expense of complicated transceiver design. With frequency spectrum sharing mode, the D2D user generates interference to the existing cellular networks either in downlink or uplink. Thus the resource allocation for D2D pairs should be designed...
Transmit beamforming can be performed to achieve capacity gains by spatially multiplexing multiple users and reduce outages by spatial interference mitigation. In this paper, we investigate the multiuser multiple input single output (MU-MISO) transmission in a two-tier femtocell network where base stations in each tier follow an independent Poisson point process (PPP), and provide insights into the...
Wireless access through a large distributed network of low-complexity infrastructure nodes empowered with cooperation and coordination capabilities, is an emerging radio architecture, candidate to deal with the mobile data capacity crunch. In the 3GPP evolutionary path, this is known as the Cloud-RAN paradigm for future radio. In such a complex network, distributed MIMO resources optimization is of...
Femtocells tend to be large scale and self-organized, which complicates the interference environment of mobile networks. In this case, interference between femtocells cannot be ignored, casing the restriction of the usage of wireless resources. Meanwhile, traffic classes are booming in recent years, and it is very likely that different traffic types with different QoS demand contend with resources...
In the cellular network, Device-to-Device (D2D) communication is considered to be a promising resource reuse strategy, which can enable local service opportunities and reduce system load for short-range communication. In order to suppress the interference from D2D users, the scheduler should allocate resources and select communication mode appropriately. In this paper, we analyze the constraints and...
Device-to-Device communication enables high-speed services in the traditional cellular networks but brings potentially mutual interference. In this paper, the heterogeneous network of D2D and IMT-Advanced in a single cell is considered, where the D2D communication is assumed to share the uplink resource with cellular user. The definition of mode selection is first introduced and then a novel distance-dependent...
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