Nancy Gohring has a very interesting piece on The HSPA Threat:

Future cellular technologies are poised to steal some potential market share from WiMax: Many of the GSM cellular operators are moving toward deploying HSDPA followed by HSUPA, which increases uplink speeds. The initial launches of HSDPA are likely to support around 1 Mbps on the downlink per user, with speeds increasing with future upgrades. Because the cellular operators already have networks in place, they are well-positioned to introduce a ubiquitous or near-ubiquitous network, should they choose.

…Simon Beresford-Wylie, senior vice president, EMEA for Nokia s networks division noted that HSDPA will likely offer more in terms of mobility while WiMax ought to offer faster throughputs. He suggested that cellular operators might use WiMax networks to supplement their networks in metropolitan areas. When pushed on the issue, he said that some cellular operators might use WiMax while some new operators might deploy it to compete with the cellular networks.

It’s a battle royale between cellular and WiMax. The bluster has begun.

Annie Lindstrom in Broadband Magazine says, “If you ask 100 different people what physical layer transport is best suited to provide optimum performance in portable and mobile wireless broadband data networks, you ll get 100 different answers”.

Clearwire, which uses NextNet OFDM gear (above), says that CDMA systems can only deliver fast speed near the tower. CDMA speeds drop rapidly with distance. That means more towers, slower speeds or fewer users. If many users watch video on EV-DO, cellular providers will be in trouble, say WiMax proponents. EV-DO will require more cell sites for blanket coverage, they warn.

WiMax aims to be cheaper and faster then celllular. Using the licensed 2.5 Ghz band, Mobile WiMax proponents claim their upfront costs are less for the same coverage. They plan to deliver WiFi speeds with cellular range. At 700 Mhz, WiMax might cover the same range with one third the towers.

OFDM proponents say OFDM is more effective in handling multipath and it’s more spectrally efficient. There is no upper limit to the data speed you can achieve with OFDM. OFDM will always provide twice the capacity of CDMA, claims Hatim Zaghoul, CEO of Wi-LAN, which holds many OFDM patents.

Greg Raleigh, invented the version of OFDM used by 802.16. In the 1990s, he founded Clarity Wireless, the first company to ship an OFDM fixed wireless data link. Raleigh is now CEO of Airgo Networks, the MIMO pioneer.

Qualcomm, the Big Daddy of CDMA, chose OFDM for their 700 Mhz MediaFlo system to provide multi-media entertainment to mobile users. The nationwide network is scheduled for completion by 2006.

Central to the MediaFLO service is the development of two key multicast technologies to increase capacity and reduce cost of content delivery to mobile handsets. These are 1xEV DO Platinum Multicast, an evolution of CDMA2000 1xEV DO, and FLO (Forward Link Only) technology, which is complementary to CDMA2000 and WCDMA networks. QUALCOMM is targeting the MediaFLO system for BREW (Binary Runtime Environment for Wireless) operators with deployed CDMA2000 1xEV DO networks (Verizon & Sprint).

Both MediaFLO and Crown Castle’s 1.7 GHz network (with Cingular and T-Mobile as potential clients), have abandoned CDMA for mobile media delivery with OFDM.

Verizon, on the other hand, uses a CDMA-based EV-DO network for their BroadbandAccess which can carry V-CAST video services.

In March 2001, Verizon Wireless and Lucent announced a three-year contract with a value of around $5 billion to upgrade their network. The agreement includes the provision of Lucent Flexent family Mobile Switching Centers (MSC) and base stations, Softswitch-based access systems for Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) network applications. Nortel Networks will expand the current network and upgrade equipment to EV-DO following an agreement believed to be worth $1 billion.

The first implementation of Verizon’s EV-DO delivers 300-500kbps downstream (1.4 Mb/s under the tower) and about 64kbps upstream. EV-DO Rev. B results in roughly 3.1 Mb/s downstream and 1.8 Mb/s upstream (under the tower), which would improve the technology’s ability to support voice-over-IP (VoIP) services on its data-only channels as well as symmetrical video phone service.

Sprint went with EV-DO after they realized that they could deliver VoIP via EV-DO (Rev.B) enhanced up-channel — and didn’t have to wait for the 3G EV-DV (Data and Voice) standard.

Sprint EV-DO coverage maps (my hometown, above), appear to show EV-DO coverage more restricted than 1XRTT (with 40-60kbps).

CDMA has supporters for broadband wireless metro networks, too.

IPWireless uses Time division, TD-CDMA. Only one channel (rather than a cellular pair) is required. They went with TDD over WiMAX because it offered mobility. Soma, founded in 1998, chose W-CDMA as its air interface in order to bring its Amosphere system to market as quickly as possible.

Cingular plans to leapfrog both Verizon and Sprint with GSM-based HSPDA.

Cingular Wireless, based in Atlanta, is the largest wireless carrier in the United States serving more than 49.1 million subscribers. In November 2004 Cingular Wireless announced that it would commercially launch High-Speed Downlink Packet Access (HSDPA) in 2005. The Cingular UMTS / HSDPA network will initially support data speeds of up to 3.6Mbps (the top speed of the first generation of HSDPA-ready devices expected to become available during 2005). Speeds will increase and will ultimately approach the theoretical maximum of 14.4Mbps as more advanced devices become available.

The network expansion will be handled by Lucent Technologies, Ericsson and Siemens. But, like “standard” 3G (using W-CDMA), it will require a major change. It needs 5 Mhz channels instead of the 1.25Mhz channels used by nearly every cellular carrier in the United States today. New basestations and handsets will be necessary.

High-Speed Downlink Packet Access (Nokia and Siemens), promises to deliver up to 10 Mbps to mobile users. It combines Adaptive Modulation/Coding (AMC) and fast packet scheduling. Traditionally, 3G systems used power control to maintain link reliability. HSDPA holds the transmission power constant and uses adaptive modulation and coding (AMC) for link adaptation.

UMTS/HSDPA also has the ability to have simultaneous voice and data sessions. A customer can use a handset to make a call at the same time they’re checking e-mail. Nokia (a supporter of both technologies), says that’s a key differentiator between UMTS/HSDPA and other wireless technologies (like IP-Wireless or EV-DO, presumably).

T-Mobile doesn’t plan 3G until 2007. Meanwhile, they’ve got Starbucks WiFi.

The WiMax/WiFi duo will be tough competition, says America’s Network. Cellular carriers offering EV-DO/HSPDA service will have to develop new content, devices, applications, business models and billing systems. But wireless ISPs, using WiMax, can just be ISPs — with tiered service levels. Easier to manage.

Intel believes scalable OFDM is the way to go with WiMax. They claim it’s more cost/effective because WiMax uses IP all the way (so today’s internet applications can be used), it’s simple and cheap (a “hotspot on steroids”), the rugged adaptive modulation can blast a signal through windows, it delivers faster speeds with better range, and handles multipath better. Not to mention MIMO and other techniques like basestation beamforming that promise enhanced speed and range.

WiMax supports Advanced Modulation and Coding (AMC) subchannels, Hybrid Automatic Repeat Request (H-ARQ), high-efficiency uplink subchannel structures, MIMO antennas, as well as other OFDMA default features, combined with the Medium Access Control (MAC) that can deliver QOS (and VoIP).

Broadband wireless pioneer Navini has dumped their proprietary CDMA-based system for OFDM-based WiMax. So have others. The WiMax Forum, now has some 270 member companies, among them the largest telecommunications companies in the world.

Clearly cellular operators are going to off load the big payloads, like multi-media, to multicasters like MediaFLO and Crowncastle. But whether they can convince subscribers to stay off the CDMA data lines (through price) remains to be seen.

Can cellular operators make money with 300-500 kbps wireless broadband (everywhere) costing $25-$50/month? It may be tough. WiMax and OFDM proponents say they can.

Posted by Sam Churchill on Friday, June 17th, 2005 at 9:50 am.