Section 2: Overview of Wireless Broadband Networks

Transcription

1 Section 2: Overview of Wireless Broadband Networks 2.1 Introduction to Broadband Network Elements Over the past decade, technological innovation and a motivation to deploy broadband in new, efficient ways has made wireless broadband a significant part of the telecommunications landscape. These technologies may be used in combination with other types of telecommunications infrastructure, such as fiber optic, copper lines, and cable. Today, wireless technologies are incorporated into different segments of telecommunications systems. For the purposes of this document, these segments are called: last mile and backhaul. The last mile of the telecommunications system is the connection between the enduser and the point of distribution for broadband services. In the Connects Beta Test Networks, the last mile segment was accomplished by end-users accessing a standards-based b/g 1 WiFi signal being transmitted on frequencies that are easily accessible by most wireless internet-enabled computers. In wire-based broadband systems, such as Digital Subscriber Line (DSL) or cable television modem broadband, this last mile is either the copper telephone line infrastructure or the coaxial cable infrastructure. In some urban markets, the last mile is provided by fiber optic cables that connect directly to the residence or business. One common point of distribution for services carried over copper telephone lines is the Central Office. A Central Office (CO) is a small structure that houses the necessary telephone switching equipment for telephone services. It can also be equipped to provide DSL services to end-users served by the CO and located within a specific distance. The backhaul is the connection between a broadband distribution point and the Point of Presence (POP), which is where a regional telecommunications system is able to connect to the greater global system. In Western Massachusetts, the primary POP is located in Springfield. The backhaul carries the aggregated bits of information from end-users that have been collected from a distribution point. This backhaul can be wireless by using fixed microwave technologies that are located on towers or buildings, that then connect to the POP. The backhaul can also be transmitted by wire-based technologies, like copper telephone lines or fiber optic cables. In the Connects Beta Test Networks, the backhaul was conducted by procuring a T1 line over the existing copper telephone infrastructure. 2.2 WiFi Networks Wireless broadband networks utilize wireless technologies to provide last mile broadband access to end-users. Networks using the b/g industry standard to 1 The Institute of Electrical and Electronics Engineers (IEEE) developed standards for different wireless telecommunications devices. The standards are identified by with an affixed letter, such as b or g. Both the b/g standards are commonly found in desktop and laptop computers, and other internet accessible mobile devices. Page 5

2 transmit information are referred to as WiFi (for wireless facility). WiFi was originally designed for use indoors. However, the technology is now being scaled for outdoor purposes. Compared to the more familiar cellular wireless system, WiFi is better at transmitting high-speed data, but is characterized by a smaller footprint than cellular technology. The current standard WiFi signal can travel 200 feet carrying 54 megabits at the unlicensed frequencies within the 2.4 GHz and 5.8 GHz bands. The 5.8 GHz frequency can carry more bandwidth than 2.4 GHz, but it does not transmit as well through physical barriers such as foliage or buildings. This difference in capacity and limitations was an important factor in selecting the technologies for the Beta Test Program. The Beta Test Program enabled end-users to access the network at b/g standards, which only uses the 2.4 GHz frequency band. The 5.8 GHz frequency band requires n standards. Generally, wireless technologies are less expensive and quicker to deploy than wired broadband technologies, including cable, copper lines and fiber optics. However, wireless equipment has a limit to its capacity and is vulnerable to obsolescence, as these technologies rapidly evolve. In many cases, wireless technologies may be a viable option in locations that are in need of immediate service and where more robust technologies or infrastructure are not financially feasible to be deployed. 2.3 Wireless Network Design Considerations The two key advantages to WiFi systems are that, generally, they are less expensive and quicker to deploy. However, there are also challenges to consider when designing a WiFi network. Before building a WiFi network, certain considerations need to be addressed such as who will the network serve, how much bandwidth will be required to serve the network, and how will the bandwidth get to the network. An additional consideration is the cost of the proposed network, in terms of initial equipment needs as well as ongoing operations. Later in this report, the Connects address these considerations and others when developing the Beta Test Program. Network End-users Identifying the type of end-users will help determine the support needed to meet the demand of the network. There are several categories of end-users. Different categories of end-users will generally utilize varying amounts of bandwidth at different times of the day. Categories of end-users: Residential End-users These are households who will use the connection in their home to access the internet. Network architects should determine where residents are located and how much usage they will require. Page 6

3 Business End-users/Workforce Large businesses usually need too much bandwidth to be included in a WiFi system, although some large businesses use WiFi as a backup system. WiFi works well for small- to medium-sized companies. Visitors WiFi is a logical way to provide regional tourism information to business and leisure visitors and, in the case of the Beta Test Program, to community residents located outside of the network area. Backhaul and Bandwidth Needs After deciding who will be served, how much service will be offered to end-users must be determined. This is the performance target. There are two choices when deciding how to build-out a network: (a) build-out to meet a future forecasted demand, or (b) build to current demand. Building to a forecasted demand requires spending funds up front for bandwidth that will not be used immediately. Building to a current demand will require future spending on bandwidth upgrades. Generally, the higher the performance target, the more WiFi infrastructure will need to be purchased; therefore, the higher the cost of the system. The infrastructure that will conduct the backhaul function and provide the internet bandwidth to a WiFi network must be determined. As noted previously, this internet bandwidth can be delivered via copper telephone lines (such as a T1 or DSL) or wirelessly (such as through a point-to-point wireless microwave connection). Access, Platforms, and Distribution The types of platforms used and how the bandwidth is distributed must be addressed when creating a network. Interoperability By definition, all WiFi devices conform to the b/g standards and can therefore interoperate with each other. This explains the ability to use a laptop at any hotspot that offers WiFi. Devices that are used in Wireless Internet Service Provider (WISP) networks, however, often do not work to the b/g standards and therefore do not interoperate with radios of other manufacturers. The proprietary nature of these radios is intentional. It provides an added degree of security to the network and allows the network operator to control end-user access and bandwidth usage through features that are not found in the b/g standard. A decision needs to be made about the platform to be used to access the wireless network. Access Technology In a WiFi network, the equipment that serves as the point of broadband distribution and end-user access to the internet is referred to as the access node. There are different radio technologies that can be utilized for the access node. Access nodes that consist of dual radio antennas have the ability to distribute Page 7

4 broadband access to end-users and also maintain a connection to other radios or communication devices. A network of interconnected wireless radios is referred to as a mesh network. Sightlines and Frequency Systems Clear lines of sight are necessary for unencumbered WiFi service, because WiFi technology has difficulty moving through any kind of physical barrier. Some of these barriers include hills, foliage, buildings and precipitation. One solution is to utilize high-sight areas or to install multiple radios around physical barriers. Different technology platforms have different abilities to transmit information through physical barriers. For example, lower frequency systems have a greater ability to penetrate through trees; therefore, 2.4 GHz penetrates better than 5.8 GHz, and 900 MHz penetrates better than 2.4 GHz. Each platform that supports these different frequency systems has advantages and disadvantages. For example, while the 900 MHz systems better penetrate physical barriers and extend to a greater range, they require more expensive end-user equipment to receive the signal. Network Installation The installation of network elements involves many decisions and considerations. Almost every network will vary because of the unique issues of each location. Some of the issues that may need to be considered include the following: Site Rights The location of potential end-users, topography, and permission to locate equipment are all factors to consider when determining where access nodes will be located. Whether the property is publicly or privately owned, the right to access a site needs to be established to locate the equipment. Costs related to permitting or recurring fees to lease space to locate equipment can add to the expense of creating a network. Site rights should be considered when planning installation. For example, if a community network plans to utilize street lampposts to mount WiFi hardware, it should review local bylaws and state regulations pertaining to street lampposts. In some cases, communities have enticed service providers to their area by addressing site right issues, such as facilitating access to town property; facilitating access to available fiber networks, and/or by becoming an anchor customer. Configuration and Power Issues In WiFi networks, there are many different ways to get from Point A to Point B on the network. Depending on tree foliage, the location of light poles, cell towers and tall buildings as well as hills and valleys, each system configuration will be unique. The network designer should address how they can close any large geographic gaps in radio locations within their proposed network area. When locating the network s components, the network designer must also consider how the equipment can access electricity to power the system (such as buildings, cell towers, streetlight poles, utility poles, etc.). Page 8

5 Network Management and Related Services There are other overall network management needs that will require an entity to be responsible for them. Backhaul Congestion Management The successful operation of WiFi systems is affected by the network s ability to convey data back to the greater telecommunications network infrastructure, i.e. the backhaul movement of data. WiFi systems are at risk for backhaul congestion because, like many lanes converging to one, WiFi systems require multiple access points to all utilizing the same limited space. Like a bottleneck, these multiple access points return to only one access point. One solution to this problem is to technically control how much bandwidth end-users can utilize. Network Surveillance, Fault Location and Repair The wireless broadband network will need to be monitored to address potential problems and react to any service interruptions. In the case of an actual outage, it is important to identify the problem and repair it. Network surveillance and reporting services, fault management, network maintenance and repair, and other similar functions will need to be conducted. Access and Security Management Decisions must be addressed about how end-users will access the network, such as through login accounts or an open access system. If login accounts are required, an entity will need to be responsible for issuing them. Having an established portal for login access facilitates communication with end-users and may offer a potential source of revenue, such as through advertising or providing a fee-based service 2. How the network will be secured to protect against unauthorized use or computer viruses is a critical element and will need to be managed. End-User Customer Service Technical assistance available to support current and future end-users is necessary. Assistance may include advice for improving signal strength, extending the signal strength to building interiors, and configuring an individual s computer settings to access the network. Administration and Billing Services If there are charges for broadband access, invoicing the individual end-user and the collection of these fees must be administered. Also if there are charges to end-users, a certain level of service quality and customer service must be guaranteed, and Internet Service Provider (ISP) regulatory requirements must be conducted. 2 An effort implemented in selected areas of Cape Cod called the Unwired Village ( utilizes a model that requires a login account. Page 9

6 2.4 Network Financial Considerations When developing a network, there are different categories of financial costs that must be considered. Many of these costs have been mentioned in the previous sections. In addition to the initial cost of equipment, there are ongoing costs of network management that a network developer must carefully consider as well as the potential sources of revenue that a network could generate. The following is a breakdown of some of these and other costs by category. Start-up Equipment & Installation Costs As expected, there are initial costs for creating a WiFi network. These costs include the purchase of the wireless equipment (example: radios, antennas, cables, etc.) and the service fees to install the equipment. Recurring Operational Costs The operating costs associated with a network include monthly recurring costs as well as other periodic costs. Recurring costs include: backhaul internet bandwidth; network maintenance and monitoring services; fees to provide customer service; fees to provide administration and billing service; electrical power for equipment; and leased space/siting fees for location of equipment. Other costs that will occur are related to the life cycle of the equipment being used. These are the costs associated with repairing the radios or upgrading to the next generation of technology. Financing and Potential Revenue Sources The potential sources for financing the creation of a network vary and often relate closely to the goal of the entity creating the network and who they anticipate to be an end-user. Advertising fees, subscription fees, and subsidization through grants or public funds are some of the financing options and potential revenue sources discussed later in this report. 2.5 WiFi Network Models How broadband networks are implemented may range from being completely town supported to being completely vendor conducted, or to being a hybrid model that incorporates some elements supported by the community and some by a vendor. It is the understanding of the Connects that once a fee is charged to the end-user for access to an internet network, a threshold is crossed. The entity providing the service must be a licensed Internet Service Provider (ISP) and comply with the appropriate government regulatory requirements, such as adhering to federal wiretapping laws. Some communities have pursued the option of becoming an Internet Service Provider (ISP). Often these are larger municipalities that will benefit on the return for their investment based on cost savings for communications, or they have a municipallybased utility company which has expanded its mission to include telecommunications. Small-scale networks that consist basically of a wireless hotspot (similar to the Connects Beta Test Program) are used to provide free broadband access in unserved Page 10

7 communities. However, the effort and cost of providing the backhaul and managing the network requires investment by the municipality. The Connects have reviewed municipally-based WiFi networks in Amherst, Brookline and Princeton, Massachusetts (see Appendix 2). Often successful municipally-based networks feature cost saving benefits for a municipality s communication system, access to grant funds or other resources, or are able to leverage a public utility in the community. The primary challenge for vendors interested in offering broadband access in traditionally unserved areas is the business model. If the unserved area is a distance from the Point of Presence (known as the POP ) this adds to the cost of delivering the necessary backhaul, which contributes to the overall cost of deploying the service. 3 In addition, these unserved areas are often perceived to have an insufficient customer density to support the cost of deploying broadband services. A formal or informal relationship between the community and a vendor may help alleviate some of the factors that have made the business case difficult. Aggregating customers or providing network assets may be some of the ways a community could provide support that will make a difference to a vendor. 3 The Massachusetts Broadband Institute & Incentive Fund seek to address this issue through strategic investment in telecommunications infrastructure in the Commonwealth. Page 11