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For those WCDMA carriers that are facing a capacity crunch due to the success of the Apple iPhone and other smartphones, help is as easy as HSPA+. It is an easy and cheaper upgrade, relatively, than going to LTE, and is a great solution to the capacity crunch some high-end smartphones are creating now in some of the most advanced mobile wireless networks.
HSPA+, sometimes called Evolved HSPA, describes enhancements to WCDMA that are within Releases 7 and 8. These improvements include lower latency, higher voice and data capacity, Voice over Internet Protocol support, and improved quality of service compared to WCDMA systems that are based on earlier releases. A host of technologies are used to achieve gains including fast scheduling, high-order modulation, hybrid ARQ error correction and MIMO (multiple in, multiple out) antenna technology.
Advocates for HSPA+ claim an increase of three times in voice capacity compared to release 99 due to use of VoIP. Additional increases are available with the use of MIMO and 64 QAM.
HSPA+ status
Although there are currently nearly 300 HSDPA networks, HSPA+ is deployed in only 28 of these as of January 2010. Sample HSPA+ chipsets actually began shipping in 2007 and base stations and handsets became available in 2009. However, it is also important to note that many recently deployed WCDMA base stations have been sold as HSPA+ ready. Other, and typically earlier, installed WCDMA base stations do not offer an easy upgrade path, encouraging LTE deployment.
Backers
HSPA+ is backed by the traditional GSM infrastructure vendors and is also being promoted by traditional members of the 3GPP2 group. Vendor backing is not an issue nor is carrier support.
Most major WCDMA carriers have studied HSPA+ and many of these carriers have announced upgrades, including T-Mobile USA, as well as carriers in Europe and the Asia-Pacific region. Visant Strategies anticipates that WCDMA carriers who possess easily upgradeable systems will at least proceed to the first round of HSPA+ upgrades, which are enabled through line card upgrades. MIMO implementation is expected to be less popular for the time being.
More WCDMA carriers, we believe, will turn to HSPA+ as smartphones become a commodity on many of the most advanced mobile wireless networks of the world and force the carriers’ hand in supplying enough capacity to ensure the network user can choose whichever smartphone one wants to utilize without consequence. In 2010, we still see many clamoring for the Apple iPhone due to the number of applications it allows to run and this will continue, although obviously the other smartphone platforms will also have an equal array of applications in due time. HSPA+ allows the iPhone and other smartphones to thrive today when these devices are very hot and a great sales tool for the mobile wireless network.
There are many other good reasons why HSPAplus will thrive.
–Intelligent antenna support: HSPA+ includes support for multiple intelligent antenna technologies. The 2×2 MIMO matrix that is supported by HSPA+ enables spatial multiplexing gains that can double the data rate supported with 16 QAM to 28 megabits per second.
–Upgrade complexity: Some HSPA+ features can be implemented with software updates in the base station and/or RNC. Others will require line card changes in the base station. Implementation of MIMO will require additional transmit and/or receive channels which may necessitate an entirely new base station if the existing base station cannot accommodate paths for the additional channels and antennas. As is the case with most technologies, new handsets will also be required to fully benefit from HSPA+ as backwards compatibility with earlier versions of the standard are maintained but not with the same speeds or latencies.
–Backwards compatibility: HSPA+ offers carriers a significant advantage over 4G standards because it offers roughly 75%-80% of the benefits of similarly configured 4G platforms while maintaining backwards compatibility. It can be deployed selectively and used to target only those areas that require additional capacity without deploying another network and air interface or requiring handsets to be multi-mode. However, in contrast to other 4G platforms, 4×4 MIMO is not supported by existing releases from the 3GPP.
–Proven technology: HSPA+ builds on a proven and, now, well understood air interface that has been deployed throughout the world in mobile, multi-cell configurations. OFDMA, the choice for 4G downlinks and sometimes uplinks, is new and it lacks real world, mobile cellular deployments. Odds are very high that LTE and mobile WiMAX will require multi-year teething periods and their prospective advantages over CDMA/WCDMA may be lesser than expected in real world deployments.
Over 200 million WCDMA devices were shipped in 2009, and HSPA+ chipsets are already being absorbed into existing WCDMA terminal and base station circuit designs.
Global WCDMA subscribers exceeded the 500 million mark at year end 2009. Meanwhile, HSDPA/HSUPA subscribers totaled 150 million at the same time or roughly 30% of total WCDMA subscribers, the vast majority of which are HSDPA users only.
–Recoup investment: Although it requires additional investment, HSPA+ represents an opportunity for 3G carriers to recoup investment in their 3G spectrum and networks. HSPA+ is a pay as you go upgrade that carriers can recoup investment from relatively quickly; LTE is a larger technical step and larger capital investment than HSPA+ that will require a longer, and currently uncertain, payback period.
The extent to which carriers can actually employ the bandwidth provided by LTE is another question mark; backhaul has become the major network bottleneck particularly in the middle of the network where fiber-like speeds are required and fiber itself is typically unavailable.
Visant Strategies foresees by year-end 2015 well over a half billion HSPA+ users due to these reasons as well as due to the migration to smart phones. The large jump in HSPA+ users will occur between 2014 and 2015, when subscribers will almost double from a slow, but impressive, build up over the next years.
Larry Swasey is co-founder of Visant Strategies. He has been covering wireless, network and component technologies for twenty years. In addition to managing the company and authoring studies for Visant he also frequently contributes articles to related newsletters and trade magazines, speaks at technology trade shows and is quoted by journalists. Swasey can be reached at: swasey@visantstrategies.com.
Andy Fuertes is Sr. Analyst and co-founder of Visant Strategies. Fuertes has worked in the high-tech research industry for ten years. He started his career at Information Gatekeepers in 1992 and was employed by Allied Business Intelligence from 1993 to 2002. During his tenure at ABI Research, Fuertes was promoted from the title of Analyst to Vice President of Research. He authored studies on broadband access, wireless broadband, RF semiconductors, mobile telephony, antennas, crystal oscillators, and satellite technologies. Fuentes can be reached at: fuertes@visantstrategies.com.
Analyst Angle: HSPA+ will solve those handset headaches
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