2x2, or not to? That is the Wi-Fi in handset question
The wireless industry has a decision to make: Go down the route of MIMO 2x2 802.11n or skip ahead to MIMO 1x1 802.11ac.
The industry is currently divided as to whether handsets will go down the route of MIMO (multiple in and multiple out) 2x2 802.11n or bypass this route altogether and go directly to MIMO 1x1 802.11ac.
MIMO allows multiple antennas to send and receive multiple spatial streams at the same time enabling devices to transmit and receive information simultaneously. The antenna configurations are typically: 1x1, 1x2, 2x2, 2x3 or 3x3. More antennas and streams mean faster speeds and better coverage, with fewer dead zones and dropped connections.
Despite shipments of around 120 million 802.11n-enabled handsets in 2010, none were shipped with 2x2 802.11n. Whilst the performance of 802.11n, even in 1x1, is better than that of 802.11abg utilising multiple antennas can further improve data rates, throughput and range.
There are some constraints to having multiple antennas on a handset. Integrating several antennas in a small device introduces greater configuration complexity. In addition, more antennas will add to the BOM (bill of materials); and some believe that multiple antennas will use more power. Conversely, others have argued that by taking less time to download content, the user will in fact use less energy.
Some in the industry believe that the disadvantages of multiple antennas in the handset outweigh the benefits; and it would make more sense to sidestep this solution and use 802.11ac. 802.11ac is expected to begin shipping in 4Q 2012 and will initially target the PCD market. 802.11ac should provide wider channel bandwidths, faster throughput and less interference from other devices than 802.11n, since it will operate at 5 GHz rather than 2.4 GHz.
So what’s the problem? Well, at first, cost. The 802.11ac solution will initially cost much more than an 802.11n solution. Many reckon that solutions need to get down to around $5 to make the mass market. Furthermore, it is widely felt that handsets follow technologies not lead them; and that until there are high shipments of enabled PCDs and networking equipment, there is little point in handsets being enabled with 802.11ac?
Filomena Berardi, Senior Analyst and lead Wi-Fi analyst commented on the situation: ”Despite the different views, everyone agrees that something needs to be done about mobile data congestion. Therefore, data offloading is top of the agenda for the mobile industry.”
IMS Research has reason to believe that 2x2 802.11n-enabled handsets are likely to appear on the market in 2012. Supporters of 2x2 802.11n claim that the industry cannot wait for 802.11ac. To overcome some of the issues of 2x2 802.11n there is even talk of a 2x2 802.11n combination chip that could reduce cost and footprint in the handset.