Summary

Multiple wireless options exist that potentially can support RBB services. The services discussed in this chapter—DBS, LEO, MMDS, LMDS, and 3G—overlap but have enough differences to attract their particular segment of users. Table 6-8 compares features among these options.

Table 6-8. Feature Comparison of Wireless Access Networks
Feature DBS MMDS LMDS LEO 3G
Bandwidth 500 MHz 198 MHz 1150 MHz (A-band) 150 MHz (B-band) Depends on license Teledesic has 300 MHz Multiple bands in increments of 1.25 MHz, 5 MHz, 10 MHz, 20 MHz
Spectrum range 12.2 to 12.7 GHz 2.150 to 2.162 GHz 2.500 to 2.686 GHz 27.50 to 31.30 GHz 19 GHz (downlink) 1.9 GHz
Downstream bit rate capacity Roughly 1 Gb Roughly 1 Gb Roughly 2.0 Gb 2 Mbps 144 Kbps, automotive

384 Kbps, pedestrian,

2 Mbps, indoor fixed
Return path Telco return, digital cellular, or xDSL MMDS return, telco return, digital cellular, or xDSL LMDS return 29 GHz (uplink) 1.9 GHz range, FDD
Footprint Nationwide 50 miles radius possible, but will likely be cellular 2 to 4 mile radius Roughly 300 mile diameter, in constant motion Cellular telephony spacing
Homes passed per cell Nationwide Greater than 1 million, but will likely be cellular to reach a few hundred A few thousand Thousands Few hundred
U.S. service providers DirecTV, Echostar MCI Worldcom, Sprint Nextlink, Winstar Teledesic, Skybridge Nearly every PCS service provider, eventually
Rainfall attenuation Negligible Negligible Problematic Potential problem Negligible
Challenges Lack of local content for TV Lack of a return path Must build cellular infrastructure

DBS and cable competition for video

Historically poorly capitalized service providers 		Most costly wireless rollout; many towers

Rain, foliage

Requires dense residential use; urban areas only 		Cost

Iridium legacy

Will it work?

Cooperation of national carriers 		Requires backward-compatibility with 2G and 1G cellular telephony.

Standards squabbles

International spectrum coordination

Will the market be satisfied with 2G?

Will carriers offer more than 384 Kbps, preferring to have more customers?
Facilitators Successful broadcast TV story with good content Lowest-cost infrastructure

Data services and equipment already developed based on cable modem technology

Accommodates local content TV

Can use indoor receivers

Influx of new capital from Sprint and MCI Worldcom 		Most bandwidth in both directions Accommodates local content TV Instant infrastructure worldwide, including on the high seas. Can bypass national carriers. Excellent spectrum location.

Carriers such as NTT DoCoMo are running out of 1G and 2G spectrum.

Consumers like mobility.

Extensive venture capital and product innovation.

Major thrust in Europe, which sees a market niche begun with GSM.

Table 6-9 summarizes the ways in which various features of wireless services act to challenge or facilitate their prospects for succeeding as an RBB network.

Table 6-9. Challenges and Facilitators for Wireless as an RBB Network
Issue Challenge Facilitator
Media Difficult transmission characteristics exist. Line of sight is usually required. Multipath and interference present continuing problems. Minimal installation and maintenance concerns exist. Fast service rollout will be available after the target market area is decided.
Spectrum Different spectrum allocations in different countries require coordination for global service and equipment development. The perfect spectrum allocation for broadband is missing. Spectrum is plentiful due to recent modulation and compression techniques and newly usable high frequencies. Lots more is bandwidth available when analog TV frequencies are freed.
Local content service Service is not available for DBS until spot beaming and copyright issues are resolved. Services provide market advantages to LMDS and MMDS for TV service.
Data-handling capabilities Implementation of a return path for DBS and MMDS is feasible but expensive. MMDS, DBS, 3G, and LEOs may not have enough bandwidth. Technology maps well to Internet data; high-speed forward and low-speed return paths closely map to Web access and push-mode data. LMDS will offer the highest two-way bit rate of any residential service if technological challenges are solved.
Market Technology has been late to market compared with wired infrastructures.

Wired infrastructures can manufacture bandwidth as the market requires.

Customer demand is unclear for high-speed mobile services. 		Consumers like mobility and will pay a premium for it. Technology builds on the cellular telephone infrastructure and marketing experience.
Business/ financial aspect Expenses incurred during auctions could deplete capital required for service rollout.

Real estate problems, roof rights, and tower costs are disadvantages.

Preemption of property owners and local municipalities may be required. 		Fast infrastructure rollout is possible.

Cost per home passed is lower than with a wired infrastructure.

U.S. interexchange carriers appear willing to invest, in part because it provides a bypass of LECs.

This offers an option for facilities-based bypass of telco and cable access.

This chapter completes the survey begun in Chapter 3 of specific networks that could provide RBB service. The next chapter turns to the home networking, the point at which the carrier network's responsibility ends and the resident's begins.

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