WLAN planning process:

Demand Collection

1. Detailed drawings of the coverage area are the basic requirement.

2. Different projects have different requirements. The preceding requirements are the basic requirements of most projects. If customers have any special requirements, the requirements must be taken into consideration.

Site Survey Information

Based on different scenarios and requirements, site surveys are classified into simple site surveys and detailed site surveys with consideration of the investment cost.

Simple site survey: Applicable to simple scenarios or some pre-sales projects that do not have detailed requirements on the solution.

Detailed site survey: Applicable to complex scenarios or post-sales network planning projects that have high requirements on the solution.

Planning and Design

Since different projects have different scenarios and requirements, there may be differences between the network planning solutions and focuses. Based on project support experience, planning of most indoor distributed scenarios is considered from three steps: capacity/coverage design, indoor distributed network design, and deployment design.

Capacity/Coverage Design

Capacity design:

1. The number of access users depends on the number of APs. You can only extend the signal coverage of antennas, but cannot increase the user capacity.

2. Indoor distributed APs support only the single data flow mode. The traffic rate of a single AP is 40 Mbps.

3. It is recommended the type and proportion of terminals be considered to determine the capacity.

Coverage design:

Coverage distance of antennas must be determined by taking the building structure into consideration. Recommendations are as follows:

1. Dormitory rooms, hotel rooms, and hospital wards: 10 m

2. Teaching buildings, science and technology buildings, laboratory building, libraries, and commercial centers: 15 m

3. Large-sized stadiums, exhibition halls, waiting halls, underground garages, and open indoor areas: 25 m

Indoor Distributed Network Design

Combination with a carrier's indoor distributed system:

WLAN signals are combined into a carrier's indoor distributed system through a combiner to use the same set of indoor distributed components with the carrier's system. WLAN signals and GSM, CDMA, and 3G signals are not in the same frequency band. In addition, the combiner has a high isolation. Therefore, there is no interference between signals in different frequency bands.

Precautions:

1. The existing indoor distributed components (power splitters, couplers, and antennas) must support the 2.4 GHz frequency band of WLAN. If not, the indoor distributed components must be replaced.

2. Link budget must be performed to check whether the antenna power meets the requirement of WLAN coverage. If not, links must be rectified.

3. AP Indoor distributed APs must be in a parallel topology relationship. Multiple APs cannot be cascaded in one link.

4. The combiner must have a high isolation which should be larger than 90 dB to prevent interference between 2G and 3G signals.

New independent WLAN indoor distributed system:

Scenario characteristics:

1. The deployment environment (such as hotel rooms and hospital wards) is closed.

2. Users are dispersedly distributed and have requirements for a certain amount of network access traffic.

Network construction principles:

1. A single AP is connected to a number of 4 to 8 antennas, which is the optimal number. It is recommended that a single AP be connected to a maximum of 10 antennas.

2. Usually, the distance between an AP and an indoor distributed antenna should be within 50 m. The maximum distance is recommended to be 60 m.

3. It is recommended that the output power of each antenna be the same in each indoor distributed scenario. The output power should be within 12 dBm to 18 dBm. The specific power is related to field strength and wall structure.

4. 8m Distance between antennas connected to the same AP should not be too close. Otherwise, signals of two antennas may interfere with each other. Usually, the distance is longer than 8 m.

5. Allocation proportion of each antenna's output power depends on couplers and power splitters. When the indoor distributed feeder topology is determined, the output power of each antenna is determined by the output power of APs.

(WLAN over CATV) WoC

WLAN and CATV signals are imported to the existing CATV cables using a combiner and transmitted to rooms using CATV coaxial shielded cables. These signals are finally divided by splitter panels. This implements wireless network coverage and TV signal transmission. The entire WoC construction does not need much change, and the construction impact can be neglected. The WoC system has striking advantages in the wireless system reconstruction project.

Precautions:

1. The CATV signal's frequency band is 860 MHz. Indoor distributed components must support both frequency bands of CATV and WLAN.

2. Signal combiners and WoC panels must be customized from the third-party device vendors.

3. Currently, CATV cables are SY(W)V-75-5 coaxial cables that are dedicated for CATVs. The signal attenuation of 2.4 GHz signal transmission is 50dB/100 m.

4. It is recommended that the length of lines between the AP and the WoC panel be within 50 m.

Deployment Design

AP deployment:

1. APs are deployed weak electricity rooms, power distribution rooms, and corridor walls. It is recommended that APs be installed on walls with interfaces facing the ground.

2. The distance between APs should be longer than 30 cm. APs cannot be installed in a stack. This ensures normal heat dissipation.

3. Ensure that RF cables of APs can be smoothly and firmly connected.

4. Prevent cables from being twisted with each other when multiple APs are installed. Connector cables cannot be pulled too much by RF cables and bend too much.

5. The diversity antenna mode is prevented from being setting in indoor antenna applications. A fixed antenna mode must be specified.

6. Prevent water drips and rat′s urine from causing device faults in an installation scenario. APs can be installed in a cabinet if possible.

Combiner, power splitter, and coupler deployment:

1. When WLAN signals are combined into the old indoor distributed system, pay attention to the frequency range supported by the couplers, splitters, and antennas. If they do not support 2.4 GHz, feeder components must be modified.

2. After the indoor distributed system is installed, test the Voltage Standing Wave Ratio (VSWR), which is required to be less than 1.5.

3. Passive components must be fixed by using ribbons and fasteners.

4. Antenna connectors must be tightly connected to power splitters and couplers.

Antenna deployment:

1. Omnidirectional ceiling-mount antennas must be installed on ceilings or in non-metal ceilings.

2. When installed on metal ceilings, the antennas must be exposed outside. The antennas can be installed in gypsum ceilings.

3. The antennas cannot be randomly placed and must be vertically installed to ensure beams evenly cover the specified area.

4. In areas where no ceiling is available, the antennas must be fixed using a support.

5. Indoor distributed antennas must be installed at locations where the antennas can be prevented from being sheltered by a building's cross beams. This prevents signal attenuation caused by a building's cross beams in the coverage area.

RF cable deployment:

1. Select 1/2-inch coaxial cables as RF cables. When the transmission distance is longer than 50 m, select 7/8-inch coaxial cables.

2. The bending radius of antennas must comply with technical indicators of antennas.

3. The indoor distributed network topology is planned based on the principle of shortest signal transmission length to prevent signal attenuation caused by cable transmission.

4. Trunk feeders are protected using cable troughs. In scenarios without ceiling, branch feeders are protected using PVC tubes, and cables are fixed using line codes. When cables are laid out in ceilings, there is no need to use PVC tubes.

5. Both sides of each feeder and each device must be labeled. The device's name and serial number and the feeder's direction must be marked on the label based on the identifier of design files.

Channel deployment:

1. Make confirmations with customers that local channels are available.

2. The same indoor distributed AP is connected to the same channel of signals sent by antennas.

3. Prevent co-channel interference: The same channel cannot be used in any two directions.

Scenario Introduction:

A university plans to provide network access services for students living in a dormitory building that has a high user density. Usually, indoor distributed and indoor settled APs can be sued. This scenario uses indoor distributed APs because the user capacity is large.

Scenario characteristics: 1. A large number of users; 2. A large amount of data traffic

Focuses of planning: Signal coverage and user capacity must be considered at the same time during WLAN construction.

Planning Procedure:

Requirement collection: Identifies key coverage areas and collects numbers of access users; Understand the building structure and wall materials.

Capacity/Coverage design: Determine the number and type of antennas based on the number of access users. The diversity antenna mode is prevented from being setting in indoor antenna applications. A fixed antenna mode must be specified.

Indoor distributed network design: WLAN signals can be combined into a carrier's indoor distributed system (through negotiation with the carrier). Additionally, an independent WLAN indoor distributed system can be built.

Channel planning: The AP channel of a building floor and that of the adjacent floor are distributed in cross-over mode to reduce co-channel interference.

Installation mode: It is recommended that APs be installed on walls with interfaces of the APs facing the ground. Distance between the APs must be longer than 30 m.

Power supply mode：PoE power is preferentially selected.

Antenna selection: When the signal attenuation is low (such as through wooden doors and windows), select omnidirectional antennas. When the signal attenuation is high (such as through iron doors and cement walls), select directional antennas.

As shown in the preceding figure, there are 24 rooms on each floor of the dormitory building, with a total of 96 users. The number of concurrent users is 24.

Obstacle partition: The dormitory building has a reinforced concrete structure. Rooms with wooden doors and windows are at both sides of the corridor.

Coverage design: There are two branches on this floor. Each branch combines signals of one 500 mW 802.11n AP. A total of six omnidirectional ceiling-mounting antennas are used, with each antenna covering four rooms.

Channel planning：Channels 1, 6, and 11 of this floor are set in cross-over mode.

Installation mode: Installed at the top of the corridor wall.

Power supply mode: PoE switches provide power for the entire building.

Indoor distributed products are applicable to the following typical scenarios.

The following table lists some special focuses of the typical scenarios in addition to planning principles and steps described in the preceding sections.