LTE-TDD & WiMAX: Two Peas in a Pod?


Dr. Spivey: The funny thing is that the person that he’s the closest to is the one he dislikes the most… That’s you, Mildred.
Nurse Ratched: Well gentlemen, my opinion, if we send him back to Pendleton or we send him up to Disturbed, it’s just one more way of passing on our problems to somebody else.
One Flew Over the Cuckoo’s Nest

A new whitepaper released by Intel (pdf) claims WiMAX technology is more spectrally efficient than HSPA or LTE. The report compares Mobile WiMAX with HSPA, HSPA+, and LTE. Intel says WiMAX can handle more subscribers per cell site with higher QOS.

According to the report, WiMAX is able to support 20 video streaming users per sector at 256 kbps, using a 10MHz channel, compared to 12 users at 128 kbps on an HSPA network. Furthermore, WiMAX networks are able to support a large number of users even with high monthly data usage of 12GB per subscriber.

Meanwhile, Rysavy Research white papers (pdf) shows another look at relative spectrum efficiency. It was created by cellular-centric 3G Americas’ members and compares 5+5 MHz for UMTS-HSPA/LTE and CDMA2000, with 10 MHz DL/UL=29:18 TDD for WiMAX.

The above chart does not include WiMAX Release 2 (802.16m) which has a spectral efficiency of 2.6 bits/sec/Hz, which would be higher than LTE.

WiMAX Release 2 (802.16m ) will use 4X2 MIMO in urban microcells, in a single 20 MHz TDD channel. The WiMAX Forum expects to see WiMAX Release 2 available commercially in 2011-2012.

Motorola sells both LTE and WiMAX gear. Their Base Band Unit (BBU) supports TD-LTE, FDD-LTE and WiMAX, with a Remote Radio Unit (RRU) that supports 2×2 Multiple Input Multiple Output (MIMO).

Motorola says 140 MHz will be allocated in Europe for LTE; using 2500-2570 MHz for uplink and 2620-2690 MHz for downlink. Additionally up to 50 MHz (2570 MHz-2620 MHz) will be allocated as an unpaired TDD band (pdf).

Motorola has been selected by China Mobile as the primary TD-LTE solution partner to provide indoor coverage for all major pavilions at the World Expo 2010 Shanghai China, and will also integrate and launch the world’s first TD-LTE USB dongle that supports both 2.3GHz and 2.6GHz. Beceem, Sequans and Qualcomm have all announced TDD-LTE chips for clients.

What’s the upshot?

LTE-TDD and WiMAX-TDD are two peas in a pod. LTE-TDD advantages include a closer similarity to LTE-FDD gear used by cellular carriers (although incompatible) and support from cell companies (such as China Mobile). WiMAX Release 2.0 (802.16m) advantages include the ability to work with existing Mobile WiMAX (802.16e) and the potential to use additional spectral bands (such as unlicensed 3.65GHz).

Perhaps the main advantage of both these systems is their single channel (TDD) nature. Less spectrum is wasted “listening”. That’s a big deal in data-driven networks.

The PR battle between WiMAX and LTE continues unabated. According to Ovum, “By 2014, LTE will have 109 million connections worldwide. In comparison, mobile WiMAX will have almost 55 million connections. This is in stark contrast to 2013, when parity between the two technologies is expected.”

ABI Research says more than 18 wireless operators have decided to deploy LTE. The research firm estimates that operators will spend more than $8.6 billion on LTE base station infrastructure by 2013. Infonetics Research believes LTE will be deployed rapidly and that its infrastructure market alone should reach $5 billion in 2013.

Verizon Wireless and Net4Mobility, a joint venture of carriers Tele2 AB in Europe and Telenor in Mexico will launch LTE services before the end of the year, said Scott Siegler, senior analyst for mobility infrastructure research at Dell ‘Oro which predicts wireless carriers will buy as much as $240 million in LTE gear this year.

Posted by Sam Churchill on .

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