Data that smart phones represented 45% of all new U.S. mobile device purchases in November coupled with the fact that smart phone users now make up 31% of the total U.S. mobile subscriber segment got me thinking – did femtocells just lose their relevance for capacity augment? Let’s revisit the business proposition for femtocells – smart phones generate a lot of data at home/office/airport/doctor visit/shopping mall yada yada …Femtocells can offload the data away from the macro network, went the reasoning. But does this argument hold if every smart phone being shipped came with WiFi? According to a report from ABI Research, it will be difficult to buy a new smart phone that does not have built-in WiFi in the next few years. Currently, about half the smart phones sold have WiFi. By 2014, the forecast goes, about 90 percent of smart phones will have built-in WiFi.
One of the primary drivers behind the whole femtocell business proposition was that very few 3G phones supported WiFi - reasons ranged from battery life issues to operators’ concern about giving up control of the user to a WiFi/fixed network. Increasingly, mobile operators are willing to give up control as well. Heavy traffic loads on overburdened 3G networks are forcing the operators to actually encourage their customers to use WiFi hotspots. Case in point - AT&T is encouraging all its iPhone subscribers to access its more than 20,000 Wi-Fi hot spots for free.
The hope is that the company can offload some of the traffic onto the WiFi network by encouraging subscribers to use WiFi for data-intensive activities when they’re in range of a hot spot. In this age of data-centric multimedia phones, carriers have embraced WiFi technology as a way to offload traffic from licensed spectrum and improve the consumer experience. I know my iPhone 4 switches to my home and work WiFi networks automatically when I am in range – it also provides instant updates when I am traveling about new WiFi networks that I can sign onto.
While most cell phones today use WiFi technology based on older standards, the newer specification called 802.11n is gaining traction. And by 2012 ABI says it will become the predominant WiFi technology used in mobile handsets. The benefit of using 802.11n is that it offers up to five times the download speed of 802.11g. The newer 802.11n also doubles the range of a Wi-Fi hot spot from about 100 meters to about 200 meters. It also has a few other features built into the specification that will improve the experience for mobile users. For example, since data transmissions are more efficient with 802.11n, battery life lasts longer than with other forms of 802.11 technology.
To summarize, all the principal data guzzlers – smart phones, tablets, laptops – will support WiFi – the question then is do we really need a femtocell for data?
LTE (the GSMA-adopted roadmap to 4G for GSM/UMTS carriers) has been getting a lot of attention of late. Verizon Wireless plans to begin network deployment in 2009 (using their newly acquired 700MHz spectrum) with full network deployment in 2010 and beyond. AT&T has also announced LTE rollout plans in 2012. Vodafone is also making the obligatory statements about rollout plans in 2011-2012 time frame – its ex-CEO, Arun Sarin has made snarky comments about Verizon needing LTE more than Vodafone owing to the inability of EV-DO to scale up to near-4G speeds like HSPA.
With the possible exception of Verizon, how real are these LTE rollout plans especially given the current financial turmoil? My bet is that 3G operators will look to squeeze the last ounce of return by upgrading their 3G/HSPA networks to HSPA+ (also called Evolved-HSPA or Advanced HSPA) long before they consider LTE. In fact, Japan’s Softbank Mobile has already chosen HSPA+ over LTE because of cost and backward compatibility. The reasons are as follows:
- No marked difference in spectral efficiency – LTE proponents talk about 144Mbps Downlink (DL) and 50+Mbps Uplink (UL) speeds. But realization of these speeds require available spectrum in excess of 20 Mhz. Now probably is not a good time to be buying spectrum. As the chart shows (courtesy: Qualcomm), spectral efficiency of HSPA+ (when MIMO is included) is close to that of LTE when you consider 5Mhz spectrum.
- Significant less Investment in Infrastructure – It is much easier and less expensive to upgrade HSPA to HSPA+ given that LTE is based on OFDM – a completely new modulation scheme while HSPA+ is still based on W-CDMA. LTE needs a completely new set of radio access and core infrastructure components – not only are the radio access algorithms different, the signaling and control protocols from the access to the core are also significantly different.
- Backward compatibility – It is simpler for a HSPA+ subscriber to gracefully handover to a HSPA network – the connectivity between RNC and the core (SGSN and GGSN) remains as before. Significant complexity exists for handover to be implemented between 4G/LTE and HSPA+ networks.
- Handset and terminal availability – Availability of LTE handsets may be less of an issue – clearly, the initial application for both HSPA+ as well as LTE is in mobile broadband (with USB dongles). It is reasonable to expect that HSPA+ dongles will be cheaper than those supporting LTE – given that a new semiconductor ecosystem needs to emerge that supports LTE.
I have to admit that I am slightly puzzled by Cox’s decision to go the CDMA route for their wireless network in the 700MHz band. Apparently Huawei beat out both Alcatel-Lucent and Nortel to win the business. Cox spent more than US$304 million on 22 licenses during the 700MHz-spectrum auction that wrapped up in March. It is also part of the SpectrumCo consortium, which also includes cable operators Comcast, Time Warner and Bright House Networks and holds nearly US$2.4 billion worth of AWS spectrum.