Rosewill RNX-N400LX 用户手册

wider variety of environments and traffic conditions. WMM makes it possible for home 

network users and enterprise network managers to decide which data streams are most 

important and assign them a higher traffic priority. 

 

 

ACK frame has to receive ACK timeout frame. If remote does not receive in specified 

period, it will be retransmitted.

  

 

 

MCS is Wireless link data rate for 802.11n. The throughput/range performance of an AP 

will depend on its implementation of coding schemes. MCS includes variables such as 

the number of spatial streams, modulation, and the data rate on each stream. Radios 

establishing and maintaining a link must automatically negotiate the optimum MCS 

based on channel conditions and then continuously adjust the selection of MCS as 

conditions change due to interference, motion, fading, and other events.  

 

 

Every 802.11 packet, no matter how small, has a fixed amount of overhead associated 

with it. Frame Aggregation combines multiple smaller packets together to form one larger 

packet. The larger packet can be sent without the overhead of the individual packets. This 

technique helps improve the efficiency of the 802.11n radio allowing more end user data 

to be sent in a given time.  

 

 

A GI is a period of time between symbol transmissions that allows reflections (from 

multipath) from the previous data transmission to settle before transmitting a new symbol. 

The 802.11n draft specifies two guard intervals: 400ns (short) and 800ns (long). Support 

of the 400ns GI is optional for transmit and receive. The purpose of a guard interval is to 

introduce immunity to propagation delays, echoes, and reflections to which digital data is 

normally very sensitive.  

 

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