Keywords

1 Introduction

After many years of construction, the State Grid has a good foundation in terms of site, communication network and so on [1,2,3,4,5], and has natural advantages in power access, which can provide strong basic resource support for 5G network. Aiming at this situation, this paper puts forward research on network planning in power system. The problem of optical fiber access or the high construction cost and long construction cycle of optical fiber will lead to the problem of service access. The wireless communication network is more suitable for the access of distributed terminals, especially to meet the communication needs of mobile terminals [6,7,8,9,10].

Coverage, capacity and quality of wireless communication network are the key factors. Network coverage, network capacity and network quality fundamentally reflect the service level of wireless network, and it is the part that needs to be improved in wireless network optimization. As we all know, network optimization is a complex, arduous and far-reaching work. As a new 4G technology, the content of TD-LTE network optimization has both similarities and differences with other standard systems.

2 Analysis of Service Requirements

For wireless access networks, base stations are distributed and consist of BBU, RRU and antennas [9]. RRU and antenna are deployed in the power tower or the roof of its own property, and BBU of many stations are concentrated in the power communication room. Control services and other services of the power network are transmitted back to the core network through different physical ports of BBU and different wavelengths of transmission equipment.

As far as carrying network is concerned, the three-level structure of inter-provincial trunk line, provincial trunk line and metropolitan area network is adopted, in which the inter-provincial and provincial trunk lines adopt 100G OTN technology. The metropolitan area network is divided into core, convergence and access layers, in which the access layer uses 10G of equipment to network, and the convergence layer and core layer use 40G or 100G of equipment to network.

Core network, the use of regional and provincial deployment mode, in which control, signaling, management and other network elements in the company's six branches of the provincial company centralized deployment, user-face network elements in the provinces or prefectural companies deployment, and MEC equipment can be deployed according to needs of services.

As the technical means to support the operation and maintenance of the 5G network, the management support platform mainly realizes the functions of equipment management, business distribution, billing, user management, data statistics and analysis, and adopts the mode of centralized deployment.

For security protection, a unified, flexible and scalable network security architecture is built to meet the security requirements of different security levels for different applications [11]. A eSIM security chip is deployed on the terminal side to realize the security of terminal access. Wireless network and a host network itself do not perceive user data, through the air-port encryption, IPSec to achieve transmission security. The unified identity authentication management system is deployed on the core network side to realize the identity authentication of the whole chain. Deploy firewalls or security gateways on the network boundary side to ensure security on the Internet side. 5G network slicing software and hardware isolation to achieve security isolation between service streams.

3 Link Budget

The propagation model is used to predict the loss of radio waves on various complex propagation paths, which is the basis of mobile communication network. Whether the communication model is accurate or not is related to whether the district planning is reasonable and whether it can meet the needs of construction with more economical and reasonable investment [12].

The frequency range of communication mode in network is 0.5–6 Ghz, divided into two models, dense urban area, suburban area and rural area. The formula of propagation model in dense urban area is

$$ \begin{aligned} & P_{{\text{L}}} = 161.04 - 7.1\lg \,w + 8.5\lg \,h - (24.37 - 3.7h/h_{{{\text{BS}}}}^{2} )\lg \,h_{{{\text{BS}}}} + (43.32 - 3.1\lg \,h_{{{\text{BS}}}} ) \\ & (\lg \,d_{{3{\text{D}}}} - 3) + 20\lg \,f_{{\text{C}}} - [3.2(\lg 17.625)^{2} - 4.97] - 0.6(h_{{{\text{UT}}}} - 1.5) \\ \end{aligned} $$

For suburban and rural areas, the formula used for the propagation model is as follows

$$ \begin{aligned} & P_{{\text{L}}} = 161.04 - 7.1\lg \,w + \lg \,h + 7.5\lg \,h - (24.37 - 3.7h/h_{{{\text{BS}}}}^{2} )\lg \,h_{{{\text{BS}}}} \\ & + (43.32 - 3.1\lg \,h_{{{\text{BS}}}} )(\lg \,d_{{3{\text{D}}}} - 3) + 20\lg \,f_{{\text{C}}} - [3.2(\lg 11.75h_{{{\text{UT}}}} )^{2} - 4.97] \\ \end{aligned} $$

PL is the propagation path loss in the formula, and the unit is the dB. \(h_{{{\text{BS}}}}\) is the actual height of the terminal equipment, and the unit is the meter [13]. \(f_{{\text{C}}}\) is central frequency, and the unit is GHz. d2D is the ground horizontal distance between base station and terminal equipment, and the unit is the meter. d3D is the space distance between base station and terminal equipment, and the unit is the meter. W is the width of the street, and the unit is the meter. h is the average height of the scene building, and the unit is the meter. The specific parameters are shown in Fig. 1.

Fig. 1.
figure 1

Parameters of the propagation model

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In the propagation model, the lower the frequency, the smaller the propagation loss, the farther the coverage distance, the stronger the diffraction ability, but the frequency resources in the low frequency band are tight and the system capacity is limited [14]. The higher the frequency, the greater the propagation loss, the closer the coverage, especially the worse the indoor coverage. The number of sites required for high frequency bands is much larger than that for low frequency bands. At the same time, the coverage is also affected by the height of building density, topography, vegetation distribution and so on. Appropriate increase in antenna height can reduce propagation loss. Through the analysis, the coverage radius of 5G in the 700 MHz frequency band of dense urban area, general urban area, suburb or rural area is shown in the following table (Table 1).

Table 1. Link budget
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4 Coverage Simulation

Adopt 700 MHz frequency band, select urban political and economic center area, rural area as simulation verification area [15] (Fig. 2).

4.1 Dense Urban Areas

Fig. 2.
figure 2

Schematic representation of simulation areas in dense urban areas

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Using frequency band of 700 MHz and using network planning simulation software to carry out iterative simulation, 7 stations are planned, the radius of single station coverage is about 850 m, and the station distance between each other is about 1.4 km. The simulation results are shown below (Fig. 3).

Fig. 3.
figure 3

Coverage simulation diagram of dense urban area

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Statistics on signal coverage are shown in the table below (Table 2).

Table 2. Statistical table of signal coverage in dense urban areas
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4.2 Urban Areas

The simulation area in the county is 10.14 km2, as shown in Fig. 4.

Fig. 4.
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Schematic illustration of the simulation area in general urban area

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Fig. 5.
figure 5

Schematic illustration of simulated coverage in general urban areas

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By using the network planning simulation software, the schematic diagram of the simulation area in the general urban area adopts 700 MHz frequency band, and the iterative simulation is carried out. Four stations are planned, the station distance is about 1800 m, and the coverage radius of single station is about 1300 m. The simulation results are shown in Fig. 5.

Statistics on signal coverage are shown in the table below (Table 3).

Table 3. Statistical table of signal coverage in general urban areas
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4.3 Suburban and Rural Areas

The simulation area is 12.07 square kilometers, as shown in Fig. 6.

Fig. 6.
figure 6

Schematic representation of simulation areas in suburbs and rural areas

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By using 700 m frequency band, the network planning simulation software is used to carry out iterative simulation, one station is planned, and the coverage radius of one station is about 3000 m. The simulation results are shown below (Fig. 7).

Fig. 7.
figure 7

Schematic diagram of coverage simulation in suburban and rural areas

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Statistics on signal coverage are shown in the table below.

Name

Arae (km2)

Percentage of coverage %

Coverage Forecast (700M)

12.073

100

RSRP >  = −90

1.493

12.567

RSRP >  = −95

6.367

53.594

RSRP >  = −100

9.76

82.155

RSRP >  = −105

10.953

92.197

RSRP >  = −110

11.508

96.869

RSRP) >  = −115

11.88

100

RSRP >  = −120

11.88

100

Compared with the link budget, the coverage radius is basically the same as that of the link budget.

5 Capacity Planning

Based on experience, the simulation is divided into four different scenarios,core-intensive area, business-intensive area, business-based area and business-dispersing area. The simulation results of the business model in the core dense area are shown in the following table (Table 4).

Table 4. Service model simulation estimation in dense areas
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The service model estimates for the three regions are shown in the table below (Table 5).

Table 5. Service model measurement tables for various scenarios
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Under the definition of 3GPP, three different types of services will emerge in the next 5G in the future, that is eMBB, mMTC and uRLLC. eMBB service requires high rate, mMTC service requires high connection number and power consumption standby, and uRLLC service requires high delay and reliability.

The following is a simple calculation of the capacity of a single station and the whole network.

The system with 30 M bandwidth has 156 resource blocks, 30 kHz subcarriers 12 subcarriers, and the spectrum utilization is 93.6%.

Modulation mode is 256QAM, downlink support 4 streams, peak throughput of single cell is as follows

$$ 30 \times 8 \times (948/1024) \times (12/14) \times 4 = 0.75\,{\text{Gbps}} $$

Modulation mode is 256QAM, uplink support 2 stream, peak throughput of single cell is as follows

$$ 30 \times 8 \times (948/1024) \times (12/14) \times 2 = 0.375\, {\text{Gbps}} $$

From the above analysis, we can see that the current configuration of base station can meet the needs of the services.

6 Conclusion

Driven by the construction of power Internet of things, the services of power grid stock needs to be optimized and upgraded, the emerging services is booming, the requirement of the network security is higher and higher, and all kinds of services require higher and higher wireless communication index. Network with low delay, large connection and large bandwidth fundamentally meets all kinds of requirements and in the construction and development of the power Internet of things, and forms a new form of power network. This paper analyzes the requirements of network and the coverage and capacity planning of network in detail. As an important infrastructure to support the development of power system, the construction of network will greatly promote the development of energy Internet strategy, and will greatly promote and all links of service in power system.