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General expressions for downlink signal to interference and noise ratio in homogeneous and heterogeneous LTE-Advanced networks

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ABSTRACT

The interference is the most important problem in LTE or LTE-Advanced networks. In this paper, the interference was investigated in terms of the downlink signal to interference and noise ratio (SINR). In order to compare the different frequency reuse methods that were developed to enhance the SINR, it would be helpful to have a generalized expression to study the performance of the different methods. Therefore, this paper introduces general expressions for the SINR in homogeneous and in heterogeneous networks. In homogeneous networks, the expression was applied for the most common types of frequency reuse techniques: soft frequency reuse (SFR) and fractional frequency reuse (FFR). The expression was examined by comparing it with previously developed ones in the literature and the comparison showed that the expression is valid for any type of frequency reuse scheme and any network topology. Furthermore, the expression was extended to include the heterogeneous network; the expression includes the problem of co-tier and cross-tier interference in heterogeneous networks (HetNet) and it was examined by the same method of the homogeneous one.

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Example of heterogeneous network.
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f0020: Example of heterogeneous network.

Mentions: As mentioned before, 3GPP developed LTE-Advanced which is the 4G technology to improve the network and set the requirements of the International Mobile Telecommunication-Union (IMT-U). The most significant improvement in the 4G technology is the ability of implementing heterogeneous networks to improve the spectral efficiency per unit area [9]. As mentioned above, the heterogeneous network is the network of base stations of different transmission powers. In other words, the heterogeneous network is the network that consists of macrocells with low power nodes such as pico and/or femto cells as shown in Fig. 4[10], [11]. The main difference between the macrocells and the low power nodes is the amount of transmission power of the base station (enodeB). Deploying these low power nodes with the macrocells became more essential due to different reasons. Firstly, it can offload some traffic from the macrocell to improve its capacity. Secondly, it can overcome the problem of dead holes and improve the overall coverage of the macrocell and also improves the spectral efficiency at the cell edge. However, the interference becomes the predominant problem in heterogeneous network due to using the same frequency band for macrocell and low power nodes. It can be divided into two different types. Firstly, the interference between the neighbouring macrocells and this type is called co-tier interference; it is similar to the ICI in homogeneous networks. Secondly, the interference is between the macrocells and the low power nodes or between different types of low power nodes; this type is called cross-tier interference. SINR is an important factor to measure these types of interference. Therefore, the paper introduces a general SINR expression for the heterogeneous network including the co-tier and the cross-tier interference as follows:(8)SINRi=Pr,i∑m≠iMIm+μ∑m≠iM∑Lp∑z=1ZPr,z,m+Nowhere(9)Pr,z,m=Pt,zhz,mGzdz,m-n


General expressions for downlink signal to interference and noise ratio in homogeneous and heterogeneous LTE-Advanced networks
Example of heterogeneous network.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037244&req=5

f0020: Example of heterogeneous network.
Mentions: As mentioned before, 3GPP developed LTE-Advanced which is the 4G technology to improve the network and set the requirements of the International Mobile Telecommunication-Union (IMT-U). The most significant improvement in the 4G technology is the ability of implementing heterogeneous networks to improve the spectral efficiency per unit area [9]. As mentioned above, the heterogeneous network is the network of base stations of different transmission powers. In other words, the heterogeneous network is the network that consists of macrocells with low power nodes such as pico and/or femto cells as shown in Fig. 4[10], [11]. The main difference between the macrocells and the low power nodes is the amount of transmission power of the base station (enodeB). Deploying these low power nodes with the macrocells became more essential due to different reasons. Firstly, it can offload some traffic from the macrocell to improve its capacity. Secondly, it can overcome the problem of dead holes and improve the overall coverage of the macrocell and also improves the spectral efficiency at the cell edge. However, the interference becomes the predominant problem in heterogeneous network due to using the same frequency band for macrocell and low power nodes. It can be divided into two different types. Firstly, the interference between the neighbouring macrocells and this type is called co-tier interference; it is similar to the ICI in homogeneous networks. Secondly, the interference is between the macrocells and the low power nodes or between different types of low power nodes; this type is called cross-tier interference. SINR is an important factor to measure these types of interference. Therefore, the paper introduces a general SINR expression for the heterogeneous network including the co-tier and the cross-tier interference as follows:(8)SINRi=Pr,i∑m≠iMIm+μ∑m≠iM∑Lp∑z=1ZPr,z,m+Nowhere(9)Pr,z,m=Pt,zhz,mGzdz,m-n

View Article: PubMed Central - PubMed

ABSTRACT

The interference is the most important problem in LTE or LTE-Advanced networks. In this paper, the interference was investigated in terms of the downlink signal to interference and noise ratio (SINR). In order to compare the different frequency reuse methods that were developed to enhance the SINR, it would be helpful to have a generalized expression to study the performance of the different methods. Therefore, this paper introduces general expressions for the SINR in homogeneous and in heterogeneous networks. In homogeneous networks, the expression was applied for the most common types of frequency reuse techniques: soft frequency reuse (SFR) and fractional frequency reuse (FFR). The expression was examined by comparing it with previously developed ones in the literature and the comparison showed that the expression is valid for any type of frequency reuse scheme and any network topology. Furthermore, the expression was extended to include the heterogeneous network; the expression includes the problem of co-tier and cross-tier interference in heterogeneous networks (HetNet) and it was examined by the same method of the homogeneous one.

No MeSH data available.