The most important step in the planning of wireless networks is the process of frequency spatial planning. It is necessary to choose the appropriate network structure, allocate base stations, calculate coverage zone, estimate the possibility of getting radio frequency bands, develop frequency spatial channel assignment plan for base stations, adapt the plan to frequency limitations introduced by security services, forme service areas, evaluate intra-interference. EMC of the network design should be in line with radioelectronic facilities of other networks.
JSV Giprosvjaz develops frequency spatial plans of radio communications networks of the following standards: GSM / GSM-R; Wi-Fi; WiMAX; LTE; TETRA; APCO-25; UMTS; cdma2000.
Under frequency spatial planning the following tasks are solved:
- Network service area is determined based on analysis of the distribution of subscribers, available financial resources
- Base stations installation locations are selected
- Calculation of the frequency reuse factor and development of frequency plan
- Service areas control measurements are performed.
- Network optimization
We also provide consulting services in the initial design phase, namely assistance in drafting technical requirements and choosing the most appropriate equipment.
Mobile radiocommunications
The most important step in the design of broadband wireless access networks is the process of frequency spatial planning. The final configuration of the network is selected, base stations location is calculated, it is also calculated whether it is possible to provide network coverage with certain quality of service, frequency spatial plan is adapted to frequency and spatial limitations, service area formed for each base station, intersystem interference is calculated and minimized. EMC of the network design should be in line with radioelectronic facilities of other networks, the network designed should be able to provide the required network capacity.
JSV Giprosvjaz performs frequency planning of mobile radiocommunications networks of different standards: DECT, TETRA, GSM, cdma2000, UMTS / HSPA +, WiMAX and LTE.
Frequency spatial planning of mobile radiocommunications network includes several main stages.
1. Requirements to initial data are developed
TOR should specify:
- Subscribers type (percentage)
- Density of subscribers per unit or traffic density per unit
- Traffic rate required (percentage)
- Type of traffic
- Tactical and technical parameters of the equipment
- Radio frequency resource allocated for the network designed;
- Restrictions on the height of antenna masts
2. Channel budget is calculated
Channel budget calculations are made to determine the maximum allowable loss in the communications channel and an service area radius. Loss budget calculations are performed in two directions: downlink and uplink, and the resulting value is selected as the minimum of the values calculated.
The main stages of frequency-territorial planning of mobile radio networks include:
1. Requirements to initial data are developed
TOR should specify:
- Subscribers type (percentage)
- Density of subscribers per unit or traffic density per unit
- Traffic rate required (percentage)
- Type of traffic
- Tactical and technical parameters of the equipment
- Radio frequency resource allocated for the network designed;
- Restrictions on the height of antenna masts
2. Channel budget is calculated
Channel budget calculations are made to determine the maximum allowable loss in the communications channel and an service area radius. Loss budget calculations are performed in two directions: downlink and uplink, and the resulting value is selected as the minimum of the values calculated.
3. Network cluster structure is calculated
Depending on radio frequency resource allocated there are several variants of radio frequency cluster topology. Possible variants of cluster structure for three-sector sites without partial frequency reuse are shown below.
4. Coverage area calculation based on the level of the signal received
Once the network operation requirements are formulated, cluster structure is set and initial frequency plan is developed, the possibility of deploying sites selected locations is checked.
The next step is to calculate coverage area for downlink and uplink transmission.
There is a variety of propagation loss prediction tools based on different statistical and mathematical propagation models, such as ITU-R P.1546, P.1812, P.526, Cost Hata, Lonley-Rice, SUI, SPM and WLL. Based on JSV Giprosvjaz specialists' experience the closest approximation forecasting and measurement results is achieved when using P.526, SPM and WLL diffraction patterns (in Minsk area conditions). The following example shows the calculation of coverage areas of broadband wireless networks in Minsk and the use of SPM diffraction mathematical propagation model.
5. Intra-interference is calculated
On this stage intra-system EMC analysis is carried out.
Intra-system EMC analysis of BWA networks can be performed in two ways:
- with the help of ITU-R P.452 model
- with the help of specialized software (example calculation is demonstrated below)
6. Handover zones are planned
There are two possible technical handover realizations: soft and hard. Soft handover is characterized by switching of the subscriber station from one base station to another, and disconnection with the first base station occurs after establishing communication with the second subscriber station by the base station. Hard handover is characterized by the loss of connection of the subscriber station and the first base station, then the subscriber station connection is established with the second base station.
Handover between coverage areas of two adjacent sectors should be planned. It is performed in order to reduce the excessive overlap of adjacent coverage areas while maintaining the shape of radio coverage areas of individual sectors.
7. Coverage quality indicators are calculated
On this stage qualitative parameters of network functioning is performed. The main indicators of the quality of mobile wireless network include data transmission rate, bit error rate.