LTE Vs WiMAX

WiMAX and 3GPP LTE are the two wireless technologies that will eventually be used to deliver data at a very high speed (up to 100 Mbit/s for WiMAX and up to 300 Mbit/s for LTE) beyond the 3G technologies. This high speed offered by the two technologies is fast enough to potentially replace cable broadband connections with wireless and enable some existing services currently deemed to be too bandwidth-hungry to be delivered using existing mobile technologies.

Contrary to LTE which is still under standardization, WiMAX is already in the market with the first national fixed-WiMAX rollout in the 3.5GHz range was carried out by Wateen Telecom in Pakistan. However, the world's first large scale mobile WiMAX deployment is due in the US. This is the joint venture between Sprint Nextel Corp. and Clearwire Corp. and it is expected to reach 120 million to 140 million people in the U.S by the end of 2010. On the other hand, LTE is assumed to dominate world’s mobile infrastructure markets after 2011. As such, some wireless operators such as AT&T Inc. and Verizon have already stated plans to adopt LTE, with major rollouts planned for 2011 or 2012.

As it has been discussed herein, LTE is the natural upgrade path for GSM/EDGE and UMTS/HSxPA network technologies that now account for over 85% of all mobile subscribers in the world. On upgrading to LTE, the existing GSM/EDGE and UMTS/HSxPA operators can use their current infrastructure (BT towers) integrating with new equipments making the whole process to be cost effective. When compared to WiMAX, an operator has to start from ground zero to setup a WiMAX network. Therefore LTE will have a significant global advantage over WiMAX in the long term.^[14]

Operators & Vendors

Based on core network architectures of WiMAX and LTE, obviously, the two technologies will both be adopted, with LTE be the best upgrading option for GSM/EDGE and UMTS/HSxPA and WiMAX mostly appealing to cable operators. This can be seen in the US where by Sprint and Clearwire are aligned behind WiMAX, while Verizon Wireless and AT&T are behind LTE.

WiMAX is under the WiMAX forum, comprises of more than 500 vendors and mobile operators such as Vodafone. The forum was established to promote solutions based on the IEEE 802.16 standards. As for equipment manufacturers, Intel has invested billions of dollars in WiMAX research and chip sets and showed off conceptual mobile Internet devices at the Consumer Electronics. Vodafone as a mobile operator and Motorola Corp they both support WiMAX and LTE. However LTE enjoys a strong support from Qualcomm and Ericsson who decided not to support WiMAX.

From Technical Point of View

Both LTE and WiMAX use OFDMA in downlink and deploy MIMO technology, to improve reception in a single cell site. However a WiMAX network process all the information in a wider channel so as to optimize channel usage to the maximum. LTE, on the other hand, organizes the available spectrum into smaller chunks.^[8]

Since WiMAX sticks with OFDMA in the downlink as well as in uplink, LTE uses SC-OFDMA in uplink. A major drawback of OFDMA-based system is its high Peak to Average Power Ratio (PAPR). As such a high PAPR requires expensive and inefficient power amplifiers which eventually increase the cost of the user equipment and drains the battery faster . Therefore SC-FDMA is theoretically designed to work more efficiently with lower-power end-user devices than OFDM is by grouping together the resource blocks and hence reduce the need for power amplifiers.

Technology Demos

• In February 2007, Ericsson demonstrated for the first time in the world LTE with bit rates up to 144 Mbit/s^[15]

• In September 2006, Siemens Networks (today Nokia Siemens Networks) showed in collaboration with Nomor Research the first live emulation of a LTE network to the media and investors. As live applications two users streaming an HD-TV video in the downlink and playing an interactive game in the uplink have been demonstrated.^[16]

• The first presentation of an LTE demonstrator with HDTV streaming (>30 Mbit/s), video supervision and Mobile IP-based handover between the LTE radio demonstrator and the commercially available HSDPA radio system was shown during the ITU trade fair in Hong Kong in December 2006 by Siemens Communication Department.

• In September 2007, NTT DoCoMo demonstrated LTE data rates of 200 Mbit/s with power consumption below 100 mW during the test.^[17]

• At the February 2008 Mobile World Congress:

Motorola demonstrated how LTE can accelerate the delivery of personal media experience with HD video demo streaming, HD video blogging, Online gaming and VoIP over LTE running a RAN standard compliant LTE network and LTE chipset. [5]

Ericsson demonstrated the world’s first end-to-end LTE call on handheld and LTE FDD and TDD mode on the same base station platform.^[18]

Freescale Semiconductor demonstrated streaming HD video with peak data rates of 96 Mbit/s downlink and 86 Mbit/s uplink.^[19]

NXP Semiconductors demonstrated a multi-mode LTE modem as the basis for a software-defined radio system for use in cellphones.^[20]

picoChip and mimoOn demonstrated an LTE base station reference design. This runs on a common hardware platform (multi-mode / software defined radio) together with their WiMAX architecture.^[21]

Alcatel-Lucent demonstrated live high-speed video connection over LTE supporting dozens of DVD-quality and high-definition video streams simultaneously, using Alcatel-Lucent infrastructure and LGE devices.^[22]

• In March 2008, NTT DoCoMo demonstrated LTE data rates of 250 Mbit/s in an outdoor test.^[23]

• In April 2008, Motorola demonstrated the first EV-DO to LTE hand-off - handing over a streaming video from LTE to a commercial EV-DO network and back to LTE. [6]

• In April 2008, LG and Nortel demonstrated LTE data rates of 50 Mbit/s while travelling at 110 km/h. ^[24]

• Researchers at Nokia Siemens Networks and Heinrich Hertz Institut have demonstrated LTE with 100 Mbit/s Uplink transfer speeds.^[25]

• On September 18, 2008, Mobile operator T-Mobile and Nortel Networks achieved data rates of up to 170 Mbit/s for downloads and up to 50 Mbit/s for uploads. T-Mobile, the wireless business of Deutsche Telekom achieved these speeds in a car in range of three cell sites on a highway in Bonn, Germany at an average speed of 67 km/h.^[25]