Cisco Aironet 2702i AIR-CAP2702I-E-K9 Folheto

 

 

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As well as offering higher speeds, 802.11ac also delivers greater robustness than 802.11a or 802.11n. 

Consider that, to deliver 450 Mbps, 802.11n has to use three spatial streams maxed out at the sensitive 64QAM 

constellation, and with little multipath immunity: short guard interval and very little coding gain (a rate 5/6 code, so 

20 percent allocated to redundancy). Yet by going from 40 to 80 MHz, 802.11ac achieves 530 Mbps using only a 

long guard interval, 16QAM, and rate 3/4 coding (that is, 33 percent redundancy). 

We see this improvement in 

, where 80-MHz links offer higher data rates close in and farther out. In 

Wave 1, different product configurations offer different benefits, but all are a marked step up from 802.11n. 

Meanwhile Wave 2, and particularly 160 MHz, potentially offers still greater speeds. However, this improvement is 

not immediately useful, especially in the enterprise, due to the very limited number of 160-MHz channels that are 

available. 

Figure 7.    Simulation of Rate at Range for 802.11ac 

 

Regulatory considerations and 802.11ac intersect in five respects: 

● 

In some regulatory domains, new rules are needed for devices to transmit 80-, 160-, and/or 80+80 MHz 

waveforms at all: 

◦ 

Effective March 2012, greater than 40-MHz operation is allowed in the United States, the European 

Union, Australia, New Zealand, Brazil, and South Africa, and no obstacle is expected in numerous other 

countries. 

◦ 

A few countries might allow 80-MHz or 802.11ac operation only after it is ratified by IEEE. 

● 

In some regulatory domains, new tests are needed for devices that generate 160- and/or 80+80 MHz 

waveforms across adjacent subbands, where the present rules allow this (for example, 5.15 to 5.25, 5.25, 

and 5.35 GHz).