What basic RF math formula should be used as a baseline to convert an RF value in units of dBm into a value of mW?*Note: "dBm" in the formulas represents the known dBm value
Answer(s): A
Given: You are evaluating the theoretical and real-world RF gain benefits of transmit and receive features introduced by 802.11 with MIMO. This exercise allows you to quantify the features value in a real-world environment. What is the maximum theoretical signal gain of chip-based TxBF and MRC (as features) when compared to the same AP using only a single antenna for transmit and receive (effectively simulating a 1x1 chip)?
Answer(s): D
The maximum theoretical signal gain of chip-based TxBF and MRC depends on the number of antennas and the channel conditions. TxBF (transmit beamforming) is a technique that focuses the transmitted signal in the direction of the intended receiver, resulting in higher signal strength and less interference. MRC (maximum ratio combining) is a technique that combines the signals received by multiple antennas in an optimal way, resulting in higher signal-to-noise ratio and better performance. The theoretical gain of TxBF and MRC can be calculated as GTxBF=10log10(N)andGMRC=10log10(N)where N is the number of antennas. Therefore, the total gain of TxBF and MRC is Gtotal=GTxBF+GMRC=20log10(N)However, this is the ideal case and assumes perfect channel conditions and alignment. In reality, the gain is lower due to factors such as channel fading, antenna spacing, and feedback delay. According to the CWDP study guide1, the typical gain of TxBF and MRC is about 4-6.5 dBi for 2 antennas, 7-10 dBi for 3 antennas, and 10-13 dBi for 4 antennas. Therefore, the answer is D.
1: CWDP Certified Wireless Design Professional Official Study Guide: Exam PW0-250, Chapter 8, page 267.
Given:In your regulatory domain, a Tx Power Level of "1" is equivalent to 17 dBm.For every integer increment (e.g. from 1 to 2) to the Tx Power Level, the APs transmit power is halved.In units of mW, what is the actual transmit power for an AP configured at a Tx Power Level of "4"?
Answer(s): C
You told your customer that multipath fading may be mitigated simply by moving one or both of the receivers antennas a small amount, usually by one to four wavelengths away from its original position. Your customer is prepared to make the change, but does not know the wavelength for802.11ac.What is the approximate wavelength of an 802.11ac radio wave?
What is a valid 40 MHz channel configuration in the 2.4 GHz ISM band where channels 1-11 are permitted?
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