“Whether 3GPP moves beyond HSPA+ 168 depends on operators and vendors,” Chris Pearson President 3G Americas said. He said T-Mobile and Nokia Siemens Networks have been the ones aiming to push data speeds beyond 168 Mbps. But given AT and T’s acquisition of T-Mobile and its plans for rolling out LTE, it may not want to make the investment given the fact that 2×2 MIMO is required to reach the 84 Mbps and higher speeds.
Today, T-Mobile USA is deploying dual-carrier HSPA+ technology that effectively doubles the speed of HSPA+ 21 networks to theoretical speeds of 42 Mbps. The higher data speeds come about because T-Mobile is taking two 5-megahertz HSPA+ downlink carriers–each supporting theoretical speeds of 21 Mbps–and bonding them together.
For those operators that can access additional spectrum, HSPA+ technology shows a path to 168 Mbps using a multi-carrier aggregation by bonding two 20-megahertz HSPA+ downlink carriers. Australia’s Telstra is aiming to move to HSPA+ at 84 Mbps this year. And the 3GPP is considering a move beyond HSPA+ 168 by looking at data speeds of 336 Mbps, and there’s even talk of 650 Mbps, said Chris Pearson, president of 4G Americas.
Spectrum could be stitched together to double LTE speed
3GPP has standardized LTE for peak theoretical downlink speeds of up to 326 Mbps (in 20 MHz with 4X4 MIMO). Informa Telecoms & Media forecasts 3.3 billion UMTS-HSPA subscriptions and 320 million LTE subscriptions by year-end 2015.
ATT Mobility hopes to double the speeds of its planned LTE network by essentially gluing together the 700 MHz spectrum it is working to purchase from Qualcomm with its existing AWS, 1900 MHz or 850 MHz spectrum holdings. The carrier plans to use carrier aggregation technology–which is a key element in the specifications for LTE Advanced, WiMAX 2 and future iterations of HSPA+–to pull the trick off, and if it is successful the action could have a major impact on the future design of wireless networks.
Qualcomm’s MediaFLO spectrum appears to be the cornerstone of that strategy. ATT announced late last year a $1.93 billion agreement to purchase the 700 MHz spectrum Qualcomm had used for its now-defunct MediaFLO mobile TV effort. Though the transaction still requires FCC approval (and a number of smaller operators are urging the FCC to reject the transaction) AT&T hopes to supplement capacity on its planned LTE network by taking MediaFLO spectrum and pairing it with spectrum in the Advanced Wireless Services (AWS) 1.7/2.1 MHz, 1900 MHz or 850 MHz bands. Interference problems preclude the operator from bonding Qualcomm’s spectrum with AT&T’s lower 700 MHz B- and C-block spectrum.
The most likely scenario for AT&T is to bond the MediaFLO spectrum with AWS spectrum in the 1.7/2.1 GHz bands. As part of its plan to buy T-Mobile for $39 billion, AT&T said it will migrate T-Mobile subscribers off T-Mobile’s HSPA+ 1.7/2.1GHz band, and use T-Mobile’s 1.7/2.1GHz spectrum as well as ATT’s own unused 1.7/2.1GHz spectrum to launch LTE service. Of course, ATT also will use its 700 MHz spectrum for LTE.
However, if AT&T were to pair its AWS spectrum with Qualcomm’s MediaFLO spectrum, the result wouldn’t provide nationwide coverage. The license area is scattered throughout the country, and the set-up would only work in markets where AT&T owned sufficient quantities of both