The following chart lists the IEEE 802.11 wireless standards and some of their key features.
MDR=Max.Data Rate (Mbit/sec)
NT=Net Throughput (Mbit/sec)
IR=Indoor Range (ft/m)
OR=Outdoor Range (ft/m)
802.11n can utilize up to 4 MIMO (Multiple Input, Multiple Output) streams.
Therefore Max. Data Rate:
At 20 MHz: : 72.2 x 4 streams = 288.8 Mbit/sec
At 40 MHz : 150 x 4 streams= 600 Mbit/sec
Net Throughput = Speed after deducting communication overheads i.e. ‘real world’ speed.
Max. Data Rate = Theoretical maximum speed under perfect conditions.
Advantages of Wireless-N Technology
- Significantly faster.
- Better range.
- More reliable.
- Less interference issues. Can operate at both 2.4 Ghz and the less frequently used 5 Ghz range.
- When buying 802.11n equipment you are ‘future proofing’ you purchase.
- It is backward compatible with the other standards.
- The stronger coverage (link range) and performance (data throughput) compared with the previous standards comes without requiring additional transmit power.
- A significantly improved bandwidth is achieved through the use of MIMO technology (Multiple Input, Multiple Output) that allows multiple antennas and signals (up to 4 streams) to be employed. There is a linear relationship with each antenna at each end and throughput, such that:
- 2 antennas/2 streams doubles throughput .
- 3 antennas/ 3 streams triples throughput.
- 4 antennas/4 streams quadruples throughput.
- Channel Bonding, which allows 2 distinct non-overlapping channels to simultaneously transmit data, produces a significant increase in possible data transmission.
The following lists some examples of quality Wireless-N (802.11n) Routers which are cheapest online through Amazon with the links below:
|SMC SMCWGBR14-N Barricade N ProMax Draft 11nWireless
Gigabit Broadband Router
|Cisco-Linksys E4200 Maximum Performance Simultaneous
Dual-Band Wireless-N Router
It should be remembered that in order to get the full benefits of Wireless-N technology, the units within the wireless network need to support the 802.11n standard.
- Omni Directional
These emit a constant field horizontally but have a vertical directional pattern. Therefore, they work well if situated in the middle of a room but are wasteful when placed in the corner or against a wall. Not only are they needlessly transmitting against/into the wall but possible security issues arise, given that a high percentage of the signal will be transmitted outside of the building.
- Isoptropic Antenna
These produce a constant field in both the horizontal and vertical plane.
- Direction or High Gain
These focus in one direction, meaning that the signal will be ‘tighter’ and located mostly within the building. This results in a better reception but also reduces security issues associated with a strong signal being broadcast outside of the building. To achieve more gain, a larger/longer antenna and electrical capture area (Aperture) is required. This produces a narrower and more focused beamwidth; such as employed with a Horn Antenna.
- Multiple Antenna Model (MIMO Technology)
Wireless-N technology can have up to 4 antennas for superior performance.
Examples of boost wireless signal replacement antennas available through Amazon are shown below:
Part 3 in the series “How to Boost Wireless Signal” will address Non-Router Network Components.