# User-Information-Aware D2D Multicast File Distribution Mechanism
## 7 Simulation Analysis  
### Simulation Settings  
In this section, the performance of the proposed user-information-aware D2D multicast file distribution mechanism is evaluated by using MATLAB. In the proposed file distribution mechanism, the video received by the service requesters is pushed to the potential service requesters so as to improve the throughput of the D2D multicast transmission system, further increasing the spectrum and energy efficiency. Therefore, in the experimental scheme, the value of D2D multicast utility metric and transmission rate in different communication environments is mainly compared. The relationships among the transmission performance, the number of potential service requesters \(\left|U_{P}\right|\), the number of service requesters \(\left|U_{R}\right|\), the number of files \(\left|F\right|\), the weight of video's popularity \(\lambda\), and the willingness threshold to accept video push service \(P_{th}^{accept}\) are studied in this section.  
To fully verify the performance of the proposed clustering and cluster head selection mechanism, the proposed algorithm is simulated in different communication environments and compared with other schemes in the same communication environment.  
* Scheme 1: Based on user information awareness  
That is the proposed scheme in this paper, the nearby service requesters and the potential service requesters who satisfy a certain conditions constitute a D2D multicast cluster, and cluster head is selected by maximizing D2D multicast utility metric.  
* Scheme 2: Based on social-aware method [19]  
D2D multicast cluster consists only of the nearby requesters and the user who has the most stable social relationship with other users is selected as the cluster head.  
* Scheme 3: Based on interference awareness [16]The nearby service requesters constitute a D2D multicast cluster, the user who has the most stable links is selected as the cluster head.  
\(\bullet\) Scheme 4: Random cluster head selection  
D2D multicast cluster is composed of the nearby service requesters, the cluster head is randomly selected in D2D multicast cluster.  
Scheme 2 and Scheme 3 are typical solutions in the existing D2D multicast communication research, involving the user's social information and channel quality information about users, respectively. The above two kinds of information are considered in the proposed user-information-aware D2D multicast file distribution mechanism. In fact, the basic principles of the first three schemes are the same, all of which can improve the system throughout by increasing the number of multicast receivers in the cluster, so Scheme 2 and Scheme 3 are selected as the comparative experimental scheme in this paper.  
Considering a single-cell model, users are randomly distributed within the grid, and the locations of users follow the Homogeneous Poisson Point Process (HPPP) [32]. In addition, D2D communication users can reuse uplink resources with cellular users. The path fading model, Rayleigh fading model and Gaussian channel noise are considered in the channel model. The main experimental parameter settings are shown in Table 1. Notably, the parameters for any set of experiments, unless otherwise specified, are the default values in Table 1.