802.11ac Vs. 802.11n

In June 2013, the fifth and the fastest wireless standard to date, 802.11ac (first wave) was launched that succeeded the 802.11n standard. In this Techspirited article, we have highlighted the changes brought about in 802.11ac over its predecessor.

Just in case you thought 4G was the fastest wireless standard around, you should start using the newest Wi-Fi standard, 802.11ac. The 5G Wi-Fi is extremely fast, and it also has improved range over its previous versions.

Although features like low-density parity-check code, space-time block coding, and short guard interval (400ns) are carried over to 802.11ac, the latest standard has some highly improved specifications.

Before we proceed to a detailed discussion regarding these wireless standards, let us take a quick look at the major differences.

The 802.11ac standard was released by Wi-Fi Alliance in June 2013. However, the standard is expected to be released in two waves. The first one operates in 20,40,80 MHz RF frequencies, while the second wave, released in January 2014, has advanced features and operates in 160 MHz range.

The 802.11n standard was released in October 2009, after a series of draft proposals. This standard operates only in 20 and 40 MHz bandwidth.

The main reason behind the speed of the 802.11ac is the combination of increase in channel bandwidth, constellation density, and increase in spatial streams. The increase in channel bandwidth to 80 MHz (from 40 MHz in 802.11n) increases the speed by 2.16 times, while the second wave bandwidth of 160 MHz further doubles the speed. Also, there is an increase from 64-QAM (802.11n) to 256-QAM, which means, the density of constellation points increases, and thus, the speed further increases. Due to the closeness of the points, they are sensitive to noise, and data errors reduce, thus, increasing reliability. The third reason behind the increase in speed of 802.11ac standard is the increase in spatial streams, which is directly proportional to the increase in speed.

Thus, considering all these points, the 802.11ac products (low end) are 4.4 times faster than 802.11n, while high-end products are 3 times faster.

Apart from the increase in speed and channel bandwidth, there is also increase in client capacity. While the 802.11n had a maximum capacity of 30-40 clients, the 802.11ac standard supports more clients. The reason behind this is the RF range that the latter supports. The 802.11n standard operates mostly in 2.4 GHz, and rarely in the 5 GHz range. The 2.4 GHz range is a shared bandwidth between microwave ovens and Bluetooth devices. Thus, the overall bandwidth received by users using 802.11n reduces, and this limits the number of clients. In case of 802.11ac, the operating frequency range is 5 GHz, which is rarely used. Thus, there is less interference in the RF range that, in turn, increases the client capacity.

If you have been reading about advances in wireless networks, you would be aware of the term beamforming. Beamforming is nothing but identifying devices that are pinned with the router, and increasing signal strength in that particular direction. Thus, instead of spreading the wireless signals in all directions, it is strengthened in a particular direction.

As far as 11n standard was concerned, this particular feature was optional and more than one beamforming methods were mentioned. This created confusion amongst the product vendors, and thus, most of them avoided incorporating the feature in their devices. However, with 11ac standard, this technique is standardized. The null data packet (NDP) sounding method is the beamforming technique used in 11ac. Also in the second wave of 802.11ac standard, multiple MIMO is introduced, which allows simultaneous transmission to multiple users. However, due to the need of high-end antennas and signal processing methods, the multi-user MIMO is restricted in the downstream direction.

While most of us would be happy with such a high-speed wireless connection, we would also be worried about the number of devices actually using the same. As 802.11n is an older standard, almost all the routers, handsets, and laptops support it. But with the recently launched 802.11ac, this scenario can change. The latest handsets like HTC One, Samsung Galaxy S4, LG Optimus G2, Samsung Galaxy Note 3, Samsung Galaxy Round, and LG Nexus 5 support 802.11ac, alongside ASUS ROG G75VX, and Apple MacBook Air.

Theoretically, the 802.11ac standard beats the 802.11n hands down. However, it will be interesting to see whether this standard justifies its on-paper specifications or not. To know more about 802.11ac standard, you can visit the Cisco website. For now, it is clear that the 5G Wi-Fi, 802.11ac is the future with faster speeds, better range, less interference, improved power consumption, and instantaneous data synchronization.