# A Long Short-Term Memory Network-Based Radio Resource Management for 5G Network
## 3 LSTM-RRM Method
### System Model  
In a standard LTE, the radio access is mainly dependent on the Single-Carrier Frequency Division Multiple Access (SC-FDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) in uplink and downlink, respectively. The OFDMA and SC-FDMA uses the exact same radio frame structure, which helps to utilize the channel subdivision. Generally, the channels are separated as radio resources which contain domain time and  
Figure 1: Block diagram of LSTM-RRM method.  
frequency. The channel bandwidth is varied from 1 to 20 MHz in the frequency domain. Then, the total available bandwidth contains 1.4, 3, 5, 10, 15, and 20 MHz, which are separated into sub-channels of 12 sub-carriers of 15 kHz, totaling 180 kHz. The radio resource's minimum allocation unit is referred to as a Resource Block (RB). Here, the single RB has 1 ms in the time domain and 180 KHz in the frequency domain. The radio resources in the time domain are separated as Transmission Time Intervals (TTI), also referred to as sub-frames, with 1 ms duration. One frame is created by 10 TTL Each TTI contains two 0.5 ms slots, and each slot has 7 symbols. In this LSTM-RRM method, the LTE-A considered in the 5G environment is referred to as 5G LTE-A. Here, the system model contains a single cell with one eNB and a set of mobile UEs. The eNB is located in the center with UE, as shown In Figure 2. This 5G LTE-A has two different user traffics: Machine-to-Machine (M-M) and Human-to-Human (H-H) communications. The eNB has a number of resource blocks specified by RBS that are transmitted among the M-M and H-H users.  
Frequency Interleaving and Guard Interval Insertion for Minimizing the Losses through the 5G Environment  
When there is continuous data transmission in a single UE with high losses, it creates a burst error through the network. This burst error creates a higher amount of losses during the data transmission. In order to overcome the effects of a burst error, frequency interleaving is developed in the 5G environment. After performing a frequency interleaving, the Inverse Fast Fourier Transform is processed at the transmitter side. Here, the data are transmitted as time domain, not as frequency domain, because the reconstruction of input signal at the receiver side is difficult when the data is transmitted through frequency domain. The input signal transmitted through the time domain is easily reconstructed, even if it is affected by the fading. Subsequently, the signals are converted into parallel to serial. Moreover, the continuous transmission of one by one data causes symbol collision, which produces Inter-Symbol Interference (ISI). This ISI is avoided via guard interval insertion in the parallel-to-serial converted data. After performing this insertion, the data is transmitted using the LTE-A.  
In this 5G environment, the Non-Orthogonal Multiple Access (NOMA) is used for obtaining the frequency division multiplexing. The subcarrier provided by the NOMA is used by multiple UEs. Therefore, the NOMA shares the spectrum for two UE with different power in one frequency slot. In addition, the RRM is performed when the network is required to transmit the data for two different UEs in one time slot. The RRM is carried out  
Figure 2: System model.  
based on three different factors: bandwidth, power, and data rate. The 4G network only considers the bandwidth and data rate constraints, it fails to consider the power constraint. However, in this LSTM-RRM method, the power constrains also considered along with bandwidth and data rate constraints to design an effective 5G network. Here, the LSTM is used to perform the efficient RRM over the 5G environment.