Cisco Cisco Aironet 1140 Access Point 디자인 가이드

다운로드
페이지 28
3
Cisco 1140 Series Access Point Deployment Guide
OL-18384-01
  So, What Exactly Is 11n?
Figure 1
MCS Rates
All things being equal, the 802.11n PHY is able to push more data than previous 802.11 iterations. But 
to reach even higher connection rates, clients must support a mix of the following two radio 
enhancements including channel bonding and MIMO.
To further its PHY-speed cause, the 802.11n standard supports the traditional legacy 20 MHz channels 
and outlines extensions for 40 MHz operation, as well. By adding provisions to the standard to support 
channel bonding, unlike older, proprietary methods, 11n will make use of the spaces reserved between 
nonoverlapping channels to achieve increased spectral efficiency in the used bandwidth. In some 
environments, more than double the effective throughput of the two bonded channels alone may be 
realized.
The 5-GHz band boasts more spectrum than the 2.4-GHz band–enough to make 40-MHz channel 
bonding possible.