HSPA vs LTE

Lately more and more people are debating this topic in light of all the questions surrounding what is true 4G, is HSPA considered 4G, which is faster, etc. So let’s get straight to it.

HSPA vs LTE - Speeds

Starting with theoretical download speeds, HSPA+ is supposed to provide up to 42 Mbps for a single 5 Mhz channel, while LTE can provide up to 100 Mbps for a single 10 MHz. Both rates assume the use of MIMO antenna technology. Note that these rates are only possible if you happen to be the only user being served by the cell-site sector, and you happen to be within close proximity of the cell-site with a strong signal and minimal interference.

The future plans for HSPA include using multiple channels to achieve from 84 Mbps to 336 Mbps, while for LTE the plan is to hit 300 Mbps in its second phase, and up to 1 Gbps using LTE-advanced (post 2013).

As for the typical user data rates, based on today’s current state of the technologies as deployed here in the US, HSPA is delivering from 2-10 Mbps per user, and LTE is delivering between 5-15 Mbps per user. So LTE has the edge here, though less widely deployed right now.

HSPA vs LTE – Carrier Deployments

As of July 2011, there are more than 700 million HSPA subscribers worldwide, while LTE is only now making its debut. Here in the U.S. both AT&T and T-mobile are using HSPA with the difference being that AT&T started upgrading to LTE while T-Mobile would like to stick it out with HSPA in the mean time.

As for LTE in the U.S., both Verizon and AT&T are currently deploying it across their networks with Verizon being in the lead having covered 160 million pops as of August 2011. AT&T plans to cover 70 million pops by the end of 2011 and 170 million by the end of 2012. And here we’re talking pops, not subscribers. So basic LTE service will not reach maturity in the U.S. until 2013 at the earliest.

That said, HSPA will most likely co-exist with LTE for quite some time into the future as a supporting or backup network just like GSM still co-exits with HSPA.

HSPA vs LTE – Technology

HSPA is based on WCDMA (Wideband CDMA) technology, while LTE is based on OFDMA (Orthogonal Frequency Division Multiple Access). OFDMA happens to be more resistant to interference than CDMA-based systems, which means that under the same interference conditions, LTE can provide higher data rates.

LTE also supports wider channels than WCDMA which makes it more efficient in carrying more bits. To simplify, think of LTE as delivering 10 students in a van or bus, while HSPA has to deliver the same students in 2 or more cars. Studies have shown that LTE is at least twice as efficient as HSPA in terms of bits per second per hertz.

Bottom Line

HSPA and LTE are both great technologies that will most likely compliment each other for some years to come. The only time it makes a difference to you is if you are considering purchasing a cell phone right now and you’re trying to decide between an HSPA phone or an LTE phone. I recommend you go with an LTE phone to future-proof yourself and take advantage of the high data rates while the LTE network is still lightly loaded, wherever it exists. And keep in mind that 4G phones are reverse compatible with 3G, so you should be able to use your phone on 3G where 4G LTE is absent.