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Monday, March 15, 2010

LTE and WiMAX: Myths and Realities

The following LTE & WiMAX Myths & Realities, originally published on the Clearwire Investment site in 2007-08, has been extensively distributed on Internet discussion threads and blog sites. So here it is – presented once gain for your viewing pleasure. Do you agree with these myths and realities? Do these assertions hold water given what we have seen and heard in 2010?

Myth: LTE is backwards compatible with 3G.
Reality: Strictly speaking, backwards compatibility implies that a 3G device can connect to an LTE base station. This is categorically not the case. LTE requires new base stations and new client devices. An HSPA handset will not be able to connect to an LTE base station, period.
LTE advocates tend to use the term “backwards compatible” when referring to a DUAL MODE handset (e.g., HSPA & LTE) which could connect to either network. But this is not a special characteristic of LTE -- Sprint already has dual mode EV-DO / WiMAX handsets planned and KT has HSPA / Wibro & EV-DO / Wibro handsets. (Wibro is simply the Korean name for WiMAX in the 2.3 GHz band.)

Myth: The LTE standard is complete.
Reality: The LTE standard recently entered a phase where revisions are now under change control -- generally, this phase happens in 3GPP when a spec is 80% complete. The stated 3GPP target for “completion” is October 2008 and then the real work can begin to fix bugs and agree upon interoperable vendor equipment profiles.
In contrast, the mobile WiMAX spec was ratified in Dec 2005; 5 plugfests occurred between July 2006 and Oct 2007; and mobile certification began in Jan 2007.

Myth: LTE performance is better than WiMAX.
Reality: Because LTE & WiMAX are both based upon OFDMA-MIMO, there is not expected to be a significant performance delta over time. Because WiMAX will have been deployed commercially for over two years before the first LTE
network is deployed in 2010, it may have superior performance initially.

Myth: LTE is an evolution of HSPA (3G)
Reality: The 3G evolution from WCDMA to HSPA was achieved via upgrades to operators’ existing 3G networks. LTE is not a 3G upgrade -- it must be deployed in new spectrum and requires a new radio access network (base station hardware, client devices) and connection to a new “all IP” core network (different from today’s 3G core networks.)
It is possible to add LTE to existing 2G, 3G cell sites -- similar to how Sprint is re-using 70% of its existing EV-DO cell sites for its WiMAX deployment.

Myth: Operators will replace their existing 2G/3G networks with LTE.
Reality: We expect operators to maintain their existing 2G or 3G networks for the foreseeable future. These networks are very efficient for voice and have built up good coverage over the years. Similar to WiMAX, LTE will initially be deployed as an overlay data network in new spectrum. Operators will offer multi-mode handsets (e.g,. HSPA + LTE or HSPA + WiMAX) to provide the best of both worlds (coverage + high speed) to their subscribers while they build out their 4G networks over several years.
Myth: For existing 2G or 3G operators, the migration to LTE is easier than it is for WiMAX.
Reality: In the first two Mobile WiMAX deployments by major carriers with existing 3G networks (KT and Sprint), both have adopted dual mode handsets so their users can seamlessly roam between their existing 3G networks and their new WiMAX networks. WiMAX equipment suppliers and operators are working closely within 3GPP to ensure that operators with existing 2G or 3G networks can deploy WiMAX as easily and at similar or lower costs to LTE. Optimized interworking between WiMAX & 2G / 3G networks enables operators to maintain their existing networks for voice & ubiquitous coverage while building out their high speed WiMAX network for broadband data capacity.
We have found operators very supportive of WiMAX-3GPP interworking as it creates a safe, viable choice in WiMAX for their 4G technology decision.

Myth: WiMAX will not have the same economies of scale as LTE.
Reality: Intel’s first generation Wi-Fi + WiMAX embedded module has been touted as having come out at a cost to PC OEMs of less than HALF the cost of 3G-only embedded modules,[1] even though 3G modules are relatively mature. Combine these “PC economics” with the 2+ years of TTM WiMAX has -- during which it will travel down the cost curve -- and we are not expecting the WiMAX ecosystem to be cost disadvantaged.
In addition to the vibrant WiMAX Forum competitive ecosystem of over 530 companies, there’s the M-Taiwan initiative (3 dozen companies, over $1.2b USD of R&D) designed to apply “Taiwan economics” to WiMAX. Net-net: we expect WiMAX to be competitive with LTE from a cost perspective (once LTE is available two+ years from now.)

Myth: WiMAX & 3G are competitors
Reality: We expect WiMAX & 3G to be complementary. Whereas the circuit-switched voice offered by 2G & 3G networks is very efficient, WiMAX provides about 3x more data capacity than today’s 3G networks. This means operators can maintain their existing 2G or 3G network for voice & narrower-band data, and deploy WiMAX for more data intensive applications. This is exactly what both KT (HSPA + Wibro) is doing and Sprint (EV-DO + WiMAX) is planning.

Myth: WiMAX will not have as big a device selection as LTE
Reality: Even with the very first commercial Mobile WiMAX network in So. Korea, we’ve already seen a level in the variety of devices which exceeds that available for 3G today. For example, one of the most popular form factors for accessing the Wibro network are WiMAX USB dongles with integrated MP3 players and/or storage. PC economics and innovation are backing WiMAX -- so one shouldn’t apply a traditional “telecom” device model when comparing WiMAX & LTE. We also expect the M-Taiwan initiative and the KDDI consortium in Japan to help drive a level of device innovation not seen before for a new wireless technology.

Myth: WiMAX & LTE are going to converge.
Reality: Because WiMAX & LTE are so similar, some believe the two should converge. We’re not sure if such convergence will ever get traction, but for now, mobile WiMAX is two to three years ahead of LTE in terms of major commercial deployments and is moving full steam ahead.
Finally, whereas WiMAX has great traction in the 2 GHz band between Sprint, Clearwire, KT, Japan, Taiwan, Russia -- LTE spectrum is starting off fragmented. Verizon & AT&T have “unconventional” spectrum for LTE (1.7 / 2.1 GHz, maybe 700 MHz) -- bands which may end up being somewhat unique for LTE deployment, reducing economies of scale.