Vodafone appears to have been busy carrying out further field trials of HSPA+ (High Speed Packet Access Plus) in Madrid and Southern Spain.
The trials saw what are some of the fastest speeds attained by a mobile broadband device of 20Mbps, 4Mbps faster than the tests announced in January. The trial exploited MIMO (Multiple Input Multiple Output) technology which creates multiple paths between the wireless dongle and base station and further work is to take place making use of adjacent radio channels to further enhance speeds.
In terms of speeds for a solution where you are not tethered to a single location the speeds from this trial are impressive, but as the thousands of current 3G based mobile broadband users will attest to, your dongle can connect at 7.2Mbps but actual download speeds will vary significantly due to the number of users on a base station or that the signal drops even though you have not moved, only to reconnect at 115Kbps. One area which HSPA is improving is the latency of the connection. It seems that while GPRS and Edge technologies often have latency in excess of 500ms, UMTS drops this to around 300ms, HSDPA halves this, and HSPA/HSPA+ start to approach acceptable latency levels for interactive applications at around 50ms.
If mobile broadband is to succeed and be a significant competitor to ADSL2+, DOCSIS 3.0 and FTTC/FTTH services it will need to address the issue of backhaul, unfortunately the costs of this will largely be the same irrespective of how the last mile to the customer is covered. Addressing the cost of backhaul is almost more critical that the debate of what technology to use for the last mile, otherwise we may have 50Meg links to the home, but due to congestion find it only performs the same as a 0.5Meg link did back in 2000 at peak times.