Singapore is a challenging wireless environment. It is hilly, with 20-story office towers sitting next door to older three-story terrace apartments. Traffic flows over a web of mostly narrow streets and alleys, with few direct line-of-sight paths. Many users want to connect while indoors, adding the challenge of effective building penetration to the mix. Despite this, Singapore has specified a nationwide Wi-Fi network for residents and citizens to be completed in less than a year. Firetide, with its local partner iCELL, has been a key supplier to this project, and participates in the deployment. What lessons can be learned from this (and other) municipal deployments? - Select a model that works for your community
- Consider future applications
- Set clear expectations about coverage
- Select flexible and modular infrastructure
- Plan carefully
- Budget suffi cient time for site acquisition
- Test before deploying
- Optimize mesh confi guration after installation
Select a Model that Works for Your Community The government of Singapore, through its Infocomm Development Authority (IDA), has set the ambitious goal of blanketing the country with wireless technology. The service, called Wireless@SG, was unveiled in October 2006 by Prime Minister Lee Hsien Loong during an event celebrating 25 years of info-communications in Singapore. Three Internet service providers have been awarded contracts by the government, which is subsidizing the fi rst $30 million of the estimated $100 million cost of the network. The IDA has set an initial goal of universal basic coverage within one year. This will allow residents and visitors to enjoy wireless 802.11 access from laptops and PDAs anywhere in the country. Consider Future Applications The government decided that it would include Wi-Fi access throughout all regions. It also called for future applications for voice and mobility so that wireless connectivity could be tapped while on the go. The IDA has also specifi ed certain advanced features, including support for "triple play" voice, video, and data service, with options for higher bandwidth service at a premium price, and secure VPN operation for clients who require it. Firetide's mesh network offers both VLAN capability, Quality of Service (QoS) and multiple levels of encryption for network security. This allows Singapore to offer secure services to its users and to prioritize critical voice traffic ahead of data for optimal VoIP performance. Set Clear Expectations About Coverage The free Wi-Fi service is slated to be available island-wide in major indoors and outdoors public places, but not in residential or industrial areas, where broadband connections are readily available. Setting expectations upfront, and planning for reliable performance in indoor public venues (cafes, malls, government buildings) prevented issues commonly seen in some of the U.S. Wi-Fi deployments. From the technical stand-point, Firetide's products allow seamless network management from indoors to the outdoors, which eliminated the need to manage two separate networks. Select Flexible and Modular Infrastructure The placement of individual 802.11 access points to provide the best end-user coverage may not be the same location as the placement of the corresponding wireless node for the backhaul portion of the network. The mesh nodes which provide the wireless backhaul are usually best placed outdoors and relatively high up above surrounding terrain. Access points, on the other hand, may need to be indoors. In some cases, more than one access point may need to be connected to the same mesh node. Thus, it's an advantage to have a modular system, one where the mesh node and the AP can be mounted separately. Firetide HotPort mesh nodes pair with Firetide HotPoint access points to give you fl exible deployments both indoors and out.
In most cases, it's best to operate the backhaul network in the 5 GHz band. This minimizes interference with, and from, devices operating in the 2.4 GHz 802.11b/g band. However, there may be specifi c locations where a 2.4 GHz link is needed. It's best to select backhaul nodes which permit portions of the mesh to be operated on different frequencies. Firetide's Mesh Bridge mode allows you to combine multiple meshes into one seamless network.
Make sure the wireless network is transparent to all applications. The Firetide mesh network looks like an Ethernet switch to all of the Ethernet devices which connect to it. Thus, protocols designed to run on wired Ethernet work easily and transparently on the Firetide mesh. Firetide's HotView Pro mesh management application allows you to manage indoor nodes, outdoor nodes, and access points from the same application. This makes setup and troubleshooting easy. Plan Carefully Perform a site survey prior to ordering equipment. A typical site survey only takes one to two days, and it will save you substantial time and money in the deployment. Site surveys can be done remotely in part, using detailed maps and aerial photography, but there is no substitute for visiting the site first-hand to observe possible RF obstructions and other design constraints. As a rule of thumb, performing a basic site survey for a medium municipal mesh will cost 4% to 10% of the cost of the equipment. A good site survey lets you plan your installation, not "fire-fight" it. It's a good investment. Develop a clear statement of requirements. Is the installation primarily intended to provide wireless access for typical laptop users, or will the network be carrying substantial video surveillance traffic? Wireless meshes can carry multiple streams of high-quality video, but such a mesh is overkill for basic Internet access. High-power nodes and high-gain antennas can be useful, but they are not a cure-all for problem connections. Many modern buildings are sheathed in tinted glass, which is an excellent reflector of radio waves. Adding power to "punch through" a building-obscured path may create as many reflection problems as it solves. When planning your installation, evaluate the Fresnel zone for each link - the width of the path. Radio links are line of site, but they are not "laser" - they have a finite width. For example, a 1000 meter link at 2.4 GHz requires an unobstructed width of about 6 meters. Budget Sufficient Time for Site Acquisition Getting physical access to the selected site often requires advance planning. Whether a given wireless node is to go onto governmentally-owned property or private property, arrangements must be made to get actual physical access. It is often necessary to visit twice; once for the site survey and once for installation. Check for power. Not every location has power available 24/7. For example, many light poles are controlled remotely, so the power is only on when the streetlight is on. Firetide nodes can be powered from AC or DC sources, but power is required. Test Before Deploying All hardware should be unboxed, powered up,and tested in the configuration in which it will be used, before deploying it to the field. As each unit is installed, it should be tested and verified to be operating correctly prior to final weatherizing of the installation. Firetide's HotView Pro mesh management software lets you quickly set up and configure your equipment. With it, you can save specific confi guration settings and apply them to additional gear as you roll out your deployment. Outdoor installations place the severest strain on equipment. Sun, rain, humidity, wind, birds, and other environmental factors will attack equipment and installations. Use only equipment rated for outdoor use. Use good-quality components. A few extra dollars spent at installation time will save the cost of sending out a repair crew later. All connections - electrical and mechanical - should be weatherized, but only after the node has been tested. Optimize Mesh Configuration After Installation In any larger installation, there will be some node-pairs with weak RF connections. Variations in RF performance will cause these links to "flap", that is, to be up, then down, then up again. Performance of the mesh will be improved if these links are manually eliminated from the overall mesh. It's also a good idea to manually set the link speed, rather than leaving all links set to auto-negotiate the speed. HotView Pro offers tools to simplify this process. Keep HotView Pro mesh management software running continuously. HotView Pro monitors all links and accumulates statistics on link performance. This lets you go back and check for periodic or intermittent outages or interference problems caused by other RF sources. With 24/7 monitoring, you won't miss these events. |