Metro Wi-Fi: Friend or Foe? (Part 2)

As discussed in part 1 of this article, metropolitan-based Wi-Fi networks using unlicensed spectrum are now deployed in a large number of major metro centers and strategic locations, such as airports, restaurants and coffee shops. Many more deployments are lining up.

Municipal governments and utility providers are getting into the broadband services game. Just as the cable industry began to experience intense video services competition from direct broadcast satellite (DBS) providers in the mid 1990s, now the industry’s high-margin, high-speed data and voice services are under attack from municipalities and alternative broadband providers eager to use their existing rights of way, 802.11 technology and unlicensed spectrum.

Well-established telecom providers also figure in this competitive landscape. This summer AT&T announced free nomadic wireless access for its broadband subscribers to more than 10,000 Wi-Fi hotspots, and T-Mobile, which already powers some 8,500 Starbucks hotspots, launched a residential extension to its service.

Additionally, the threat from licensed wireless spectrum owners and 802.16 WiMAX technology should not be ignored. That approach is to offer fixed wireless broadband services from existing tower locations by using WiMAX technology over licensed and private spectrum. As the 802.16e mobile WiMAX standard proliferates, the service offer moves from one that is fixed in nature to one that adds broadband mobility, as well. More challenges The challenges for both rural, one-way cable operators and cable operators with two-way HFC plant in larger metropolitan centers are clear. Wireless competition for the high-speed data and voice over Internet protocol (VoIP) subscriber base through licensed WiMAX and low cost, unlicensed Wi-Fi wireless technology is only going to increase.

Let’s place that threat in a broader context. Larger, two-way cable system operators are under the gun to do the following:

• Continue to offer advanced, sticky services to retain and grow customer base
• Leverage IP/Gigabit Ethernet (GigE) core networks and offer high-speed data and voice services to commercial customers and industrial parks to increase revenues
• Extend plant outside existing franchised service areas to offer high-speed data and VoIP services to underserved neighboring communities
• Compete against WiMAX point-to-multipoint broadband wireless access by licensed spectrum owners
• Compete against unlicensed Wi-Fi overbuild by alternate operators offering nomadic and fixed wireless access to the residential customer

Even prior to facing the WiMAX and Wi-Fi overbuild threats, the smaller, one-way cable system operator is faced with even more basic challenges:

• Stem continued loss of video subscribers to DBS
• Justify, if possible, two-way HFC upgrades
• Offer advanced, triple-play services to retain and regain customers DOCSIS hotspots To meet some of these challenges in the wireless arena, technology providers have proposed solutions using DOCSIS hotspot and deep hybrid mesh architectures.

The DOCSIS hotspot architecture was designed to allow a cable operator to use its existing right-of-way assets and advanced two-way networking infrastructure to offer strategically located, advanced 802.11 broadband wireless hotspot services. The approach involves the combination of HFC compatible outside plant network packaging with 802.11 hotspot radio and DOCSIS cable modem technology.

The general hardware design intent is to create an HFC network and cable technician friendly device that combines 802.11 wireless technology with DOCSIS cable modem technology. Hence, the edge device typically is equipped with a familiar line active housing, 60/90 VAC slow start power supply, field serviceable surge suppression, JXP-style padding for "sweet spotting" cable modem levels, external -20 dB test points, DOCSIS compliant cable modem for wide area network (WAN) side data connectivity, and 802.11 compliant wireless technology.

The access radio device supports private, virtual service communities (VSCs, typically with 16 service set identifiers, or SSIDs) – essentially wireless-based Ethernet virtual local area networks (VLANs), each with its own set of attributes for quality of service (QoS), throughput, security, etc. See Figure 1. This architecture was developed to allow the cable operator to be a competitive Wi-Fi service provider, within its franchised service areas, offering 802.11 nomadic Wi-Fi broadband services to its high-speed data customer base, while also offering fee-based captive portal for noncable customers. It also enables the rental of fully private SSIDs to municipalities, emergency services, and a range of corporate and enterprise customers.

This architecture and approach not only creates value for the existing cable high-speed data customer base, but also damages the competitive business case for alternative wireless broadband providers. Deep hybrid mesh Deep hybrid mesh is another standard, architectural answer to these various challenges. Designed to allow a cable operator to provide "blanket" Wi-Fi services using existing rights of way and network infrastructures, this approach also involves a unique combination of hardware and software technologies. Overall, it combines software-provisioning technology with multi-radio IEEE 802.11 a/b/g network-based and customer hardware and multi-radio mesh-radio networking software.

As opposed to centralized tower-based wireless designs, the deep hybrid mesh approach combines modern HFC design theory with the 802.11 compliant wireless solution. It involves deep wireless node placement to provide multi-megabit broadband service delivery and a wide coverage area.

Anyone who has used 802.11 wireless technology has experienced that distance from an access point dictates the dynamically selected modulation type and achieved throughput of a wireless connection. The deep hybrid mesh approach pushes 802.11 access radios deep into the network to provide multi-megabit, low latency services and outstanding network coverage area.

On the network radio side, the standard hardware design intent is to create environmentally hardened and flexible, triple 802.11 radio devices that combine 802.11a for data transit and 802.11b/g for customer access. As with the DOCSIS hotspot architecture, each customer access radio typically supports up to 16 fully private SSIDs, with each having its own independent set of attributes. The mesh network has a root node location and multiple slave nodes as described in Figure 2. A common hybrid mesh design populates each network device with three modular, mini-PCI radios and external antennas. Two of the radios utilize 802.11a technology in the 5.8 GHz Unlicensed National Information Infrastructure (U-NII) band for high capacity transit between one or more adjacent node locations. The third radio is 802.11 b/g compliant, utilizing the 2.4 GHz ISM (industrial, scientific, medical) band for customer access.

Modular mini-PCI radio technology is chosen such that an in-service upgrade path is maintained for future radio technology upgrades. An example would be an in-service upgrade to unlicensed WiMAX technology, from 802.11a, for the data transit legs. Unlicensed, low power, WiMAX technology using the mini-PCI form factor is emerging and provides a natural transition path for higher data transit capacity in the deep hybrid mesh architecture.

The network devices are typically placed between 1,000 and 2,000 feet apart on the operator’s existing rights of way. As nodes encounter alternate paths on their transit legs, primary and redundant paths are automatically created, thereby resulting in a highly resilient network infrastructure.

Additionally, by employing low cost 802.11b/g customer premises equipment (CPE) devices with automated device provisioning, similar to DOCSIS, and traditional captive portal Wi-Fi hotspot services, an operator creates a unique service model on a common networking infrastructure. Specifically, it’s possible to offer fixed wireless access to CPE devices, complete with customer billing and automated provisioning, in addition to Wi-Fi compliant, RADIUS (remote authentication dial-in user service) authentication with captive portal for nomadic Wi-Fi devices (laptops, PDAs, cell phones, etc.).

That particular implementation of deep hybrid mesh helps the one-way system, smaller cable operator solve several pressing issues. It enables the addition of high-speed data (5-20 Mbps) and VoIP, complete with DOCSIS-like automated CPE provisioning, and nomadic Wi-Fi hotspot services on a common wireless infrastructure. This approach also sidesteps the burdensome capital and operating expense of an HFC two-way plant and DOCSIS upgrade. Finally, it is highly effective for broadband wireless network extensions into commercial areas where no HFC plant currently resides. The provisioning piece As with DOCSIS and PacketCable, the CPE in the network needs to be tied to the customer, which ties the device to the bill. The CPE device also needs to be automated in its configuration and administration, again, as is the case with DOCSIS and PacketCable today.

Integrated device provisioning enables remote management and control of the CPE device from the headend with the automated configuration of the CPE device based on a pre-described service level. This allows an operator to achieve speed of deployment comparable to that of a DOCSIS cable modem rollout while allowing the addition of new products for the customer from the headend.

Automated provisioning in the WiFi and WiMAX space had long been a missing piece of this puzzle because the CPE kit was usually seen to be open Wi-Fi Alliance-compliant and, thus, without points for integration into existing DOCSIS device provisioning systems.

New technology developments, however, combine automated wireless CPE device provisioning and customer billing with outdoor Wi-Fi network hardware, so 802.11 deep hybrid mesh networks can now be used to provide fixed wireless access services to indoor and outdoor customer CPE, as well as nomadic Wi-Fi services to laptops, PDAs and cell phones.

For a view of the high-level operation of the automated device provisioning process over the 802.11 deep hybrid mesh network, see Figure 3. This is depicted as a "top down" approach where the media access control (MAC) address of the CPE device is pre-entered into the back office provisioning system before deployment. An alternative is the "walled garden, bottom up" approach where a customer is forced to a capture page and has to enter detailed customer information to activate the CPE. Although beneficial for the cable operator, these developments in provisioning cut both ways. If utilized by an alternative service provider in a Wi-Fi overbuild scenario, they increase the broadband services competitive threat. Two cases One North American MSO has taken an aggressive stance on Wi-Fi, deploying hundreds of outdoor DOCSIS hotspots on its existing HFC rights of way in the most strategic locations of several cities.

The service model is free nomadic Wi-Fi access for existing high-speed data customers and fee-based access for all others. Activated in the spring of 2007, it has resulted in tens of thousands of sessions and piqued broader customer interest. (See Figure 4 for a typical deployment.) By using the unlicensed Wi-Fi spectrum for itself and positioning devices at the most strategic locations in its service territory, this MSO has damaged the business case of an alternative provider wireless overbuild, occupied the limited Wi-Fi public use spectrum, provided another sticky service to its cable modem customer base, and will soon achieve another revenue stream from fee-based wireless users.

On the flip side, in early 2007 an incumbent utility company overbuilt a major metropolitan center in North America with an 802.11 mesh system that allowed the utility company to offer broadband services to customers both inside and outside of their residences within the mesh network coverage area. At the time of this deployment, no competitive nomadic Wi-Fi services were available from any other broadband service providers in this city.

Coming off a successful free trial that saw 43,000 subscribers sign up for its Wi-Fi service, the utility company then moved to a subscription-based service. The results, shared in a reported interview with the utility company president, are noteworthy.

Whereas the utility had projected that 10 percent of subscribers would convert from free to paid services, it actually saw a 22 percent conversion rate. Assuming that this group of "converts" (approximately 9,500) had been paying $35 per month to one provider for high-speed data services, the potential lost revenue to the incumbent broadband provider could add up to some $330,000 per month.

More alarming still, this alternative service provider has yet to employ a CPE strategy with automated device provisioning on its deployed mesh network as described earlier. Therefore, these numbers do not include customers who do not have Wi-Fi capable computers and/or mobile devices. Conclusion The competitive pressures in the high-speed data services arena are increasing dramatically. One outcome is that customers are gaining the option to switch to alternative broadband service providers to enjoy both fixed and nomadic Wi-Fi services from a single provider.

What is a cable operator to do? The choices are clear. Use existing network assets and rights of way and befriend Wi-Fi technology, offering an additional service to high-speed data customers while countering the competitive threat. Or choose not to deploy Wi-Fi and prepare for the possible loss of high-speed data customers to alternative providers who seize the opportunity and take advantage of low cost, unlicensed Wi-Fi technology with a differentiated, fixed and nomadic broadband services offering.

802.11 Wi-Fi technology has matured greatly from its original inception in 1997. The threats and opportunities have matured along with it.

Christopher Skarica is vice president, engineering, Lindsay Broadband. Chris Busch is vice president, broadband technologies, Incognito Software. Sidebar: Getting Overbuilt? The number of U.S. municipalities getting into the Wi-Fi game has grown tremendously, from 122 in July 2005 to 385 in July 2007, according to MuniWireless.com. Is your service area already, or about to be, overbuilt? A list of U.S. municipal Wi-Fi overbuilds can be found in a report posted in the Resources section of that Web site. Sidebar: Wholesale Wi-Fi Access radios in a Wi-Fi architecture can provides deep 802.11 b/g compliant coverage areas with multiple, fully independent SSIDs. Each SSID can be independently configured for varying QoS, throughput, and security requirements.

A wholesale model, accordingly, could be employed for Wi-Fi access in coverage areas. Some examples include: private access to municipality, emergency services, local utility and telecommunications companies; location based, customized Wi-Fi captive portal service with a revenue sharing model for Wi-Fi access to customers at local businesses; and fully secure and private SSID for broadband service delivery to small enterprise customers.