Jim Bradfield, NAS Wireless
90 Via Las Flores
Rancho Mirage, CA 92270
Executive Summary of the Recommended Guidelines:
The purpose of this document is to explain the recommended guidelines when designing a wireless LAN network. This document should be used for any size or type of facility, including office spaces, healthcare, airports, and primarily warehouse/distribution centers.
The wireless network for any site must be designed with the following primary objectives:
- Support all site applications such as RF handheld scanner and printer devices, mobile carts, wireless kiosks, corporate laptops and tablets, BYOD, and VoIP phones.
- Consider any areas requiring higher throughput, such as training centers or video streaming rooms.
- Provide persistent roaming over the wireless network for all devices, including new and legacy systems.
- Provide consistent throughput and persistent roaming over the wireless network within all areas of the facilities, considering all potential sources of interference and signal obstructions.
- Support the highest requirements for data throughput and quality of service over the wireless network. This is dependent on the device types supported.
- Provide remote access configuration, troubleshooting and overall support capabilities for any wireless network.
- Install the wireless equipment in areas that are easily serviced by the local IT site contacts.
Specific Design Guidelines:
- Gather data on all device types to be supported. This is most important for warehouses/distribution centers and healthcare BioMed, especially those supporting legacy RF handheld scanner, data gathering, and printer devices. The specific capabilities of all devices must be validated and documented. This includes the specific RF channels, channel width, and transmit power supported by each type of device.
- Follow the device manufacturers’ RF planning guides for best practice. This includes but is not limited to devices such as Vocera voice badges; Zebra handheld scanners, printers, and patient monitoring devices; and Stanley Healthcare AeroScout RFID tags.
- Provide a complete and accurately scaled site plan for each location, including the dimensions for the rooms, dimensions and materials for any potential RF obstructions such as racks and shelving; office space walls, glass, elevator shafts, and stairwells; and any special areas such as loading docks and truck ramps that require wireless service.
- Conduct an on-site walkthrough of each covered area to validate the types of materials that are used in the construction of the walls, racks and other objects that might obstruct the wireless signals.
- Define areas that might provide interference to the wireless network, such as microwave ovens, machinery emitting EMI, MRI machines, HVAC or building sensors emitting RF or Bluetooth signals, and separate wireless networks located within the facility.
- Perform testing of all supported devices on the existing wireless network to get a baseline of actual operation for each type of device.
- Provide an initial Ekahau predictive wireless design based on the input from all the above data collection.
- Validate the predictive design via on-site Ekahau RF testing utilizing an active access point model expected to be used in the configured with the expected power, RF channels and data rates. This is typically referred to as AP on a stick testing. NOTE: This should be done mainly for the access point placement locations for each special area. Areas that are especially difficult may require more testing. These special locations should be specified during the initial walkthrough of the site. The purpose of this type of testing is to validate as many of the locations as possible to limit the number of change orders required. The rule of thumb is to compare the on-site testing validation against the implementation charge for the access points. If the access point installation costs are $500 per device, and the on-site active testing takes approximately $200 per unit, then testing is a good trade-off to assure that everything is correct prior to implementation. If the access point installation costs in an office area with low ceilings are $50 per unit, then it makes sense to test a limited number of access points in those areas.
- The on-site testing should be conducted with the same type and model of access point to be installed in the network.
- Multiple types of external antennas should be tested on site to validate which antennas are best for each location and obstruction area. This includes the use of integrated antenna model access points for low ceilings and where access points can be suspended down from high ceilings.
- Caveat: The results of the on-site testing are not going to be 100% reflective of the completely installed network due to the capability of wireless controllers to provide radio resource management to optimize the coverage and capacity of the fully installed network. However, the on-site testing does provide valuable information as to the properties of the interference and the building material obstructions, which are required to support design assumptions.
- Assure all access points are mounted in horizontal orientation, either on the ceilings or on walls using Oberon or other manufacturer’s brackets.
- Validate final access point locations are feasible to mount and cable.
- Provide final documentation to the cabling/installation contractor in the form of a cutsheet showing the access point number, model type, and antenna type corresponding to the locations marked on correctly scaled floor plans.
- Provide a final bill of materials for all equipment to corporate IT for approval.
- Validate with the cabling/installation contractor the number of access points that are to be terminated into each existing IDF. If cables are out of length, new IDFs may be required to accommodate the access points.
- Validate with the IT team the capability of the network switches in each IDF to support Gigabit connections and provide enough power over Ethernet to support the total number of access points in each switch in each IDF.
NOTE: The on-site Ekahau testing with an active access point should take approximately 1-2 hours per access point location.
- Validate the cable tests for each location to assure everything is within approved length.
- Validate all access points are mounted according to recommended heights and orientations.
- Configure the new wireless system to support all applications and device types and gather information for the correct SSIDs, VLANs and authentication.
- Test all the SSIDs and VLANs to confirm everything is operational. This requires turning up a few access points to test device interfaces and network communications during a change control.
- Perform an on-site Ekahau + iPerf test for all wireless areas of coverage to confirm that the wireless network is functioning as expected.
- Test and document all wireless devices to be supported prior to cutover. This includes providing a test configuration for each device, along with specific configuration steps and details, and doing tests on the new network during a change control.
- Validate that the specific device type can persistently roam and connect in all areas for the new network.
- Validate configurations required to support the new wireless network on all wireless devices are correct and that all specified changes have been made and accepted on each wireless device.
- During the cutover, validate that all devices are functioning as expected and compare the operation in the new environment to the baseline data gathered from the existing environment.
- Provide final documentation on a final cutsheet and floor plans for all access points, including locations, names/numbers assigned to each access point, mounting heights and specific access point models with antenna types for each location.
- Provide final switch port and patch panel ports for each access point and provide configuration for VLANs and network interfaces for each switch and the wireless controller.
- Provide documentation for all areas above including “lessons learned” with specific changes in requirements for each device.
- Publish the final findings for each location cutover to be used as a reference for all new networks.
The primary objective for the wireless network for any site is at the start of the project, to gather the highest level of detail possible about the operation of each site, including all the required feature capabilities for each application/device supported over the network.
While this approach may appear to be more costly up front, adhering to the recommended guidelines results in a better return on investment through avoidance of multiple change orders, additional funding, failed testing, and multiple reconfigurations. This results in higher employee satisfaction and improvement in overall productivity for the site.