With pre-IEEE 802.11n products, the maximum speed reached in late 2007 is 108 Mbit / s, that is to say double the IEEE 802.11a and 802.11g standards. This flow rate is achieved by increasing the density of transmitted bits. Technological advances are such in the field of radio transmission it is now possible to improve greatly this flow. 802.11n networks offer a potential gross rate of 540 Mbit / s. In fact, the actual flow rate is much lower and is of the order of 100 Mbit/s in the best case.
The goal of the IEEE 802.11n standard is threefold:
• Make changes to MAC and PHY levels so that the flow exceeds 100 Mbit / s to best achieve 540 Mbit / s. For this technology MIMO is implemented.
• Improve greatly useful system throughput at the application level to get one hundred megabits per second.
• Stay compliant with IEEE 802.11a and 802.11g.
It is understandable the first and last goals. The second is no less clear if one recalls the disastrous actual flow rates of the first Wi-Fi networks: 5-6 Mbit / s at best in the case of 802.11b and about 20 Mbit / s for 802.11a and 802.11 g. The objective of the new standard is to provide an effective transfer rate of about 100 Mbit/s.
IEEE 802.11n is a milestone in product compatibility since it includes the IEEE 802.11i standard for security and confidentiality of data transport over the air interface. This standard is not completely compatible with the first two generations, especially with the use of AES, the strong increase in speed is an opportunity to encourage users to completely change their wireless network infrastructure.
The IEEE 802.11e standard, that we detail a little further, to provide a quality service around DiffServ type technology is also included in 802.11n. This integration will give priorities to different flows that pass through the wireless network.
The IEEE 802.11n standard allows to natively manage mobility by integrating the IEEE standard 802.11f. On a wireless network, you can switch to another wireless network, even though the mobility management is done only low speeds, pedestrian type.