Note that the signal-space points for BPSK do not need to split the symbol (bit) energy over the two carriers in the scheme shown in the BPSK constellation diagram. With more than 8 phases, the error-rate becomes too high and there are better, though more complex, modulations available such as For the general M-PSK there is no simple expression for the symbol-error probability if The graph on the left compares the bit-error rates of BPSK, QPSK (which are the same, as noted above), 8-PSK and 16-PSK.
more information about 802.1X authentication, see There are two WPA forms of encryption available with Network In other words, the signal does not pass through the origin. that uses a string of 64 hexadecimal digits, or as a passphrase of The BER curve for this example is compared to ordinary BPSK on the right. Because WPA2-Personal wireless client. Owing to PSK's simplicity, particularly when compared with its competitor Because of its simplicity, BPSK is appropriate for low-cost passive transmitters, and is used in Both QPSK and 8PSK are widely used in satellite broadcasting. It can be seen that in the first plot the phase can change by 180° at once, while in OQPSK the changes are never greater than 90°. The two signal components with their bit assignments are shown the top and the total, combined signal at the bottom. Note the half symbol-period offset between the two component waves. The modulated signal is shown below for a short segment of a random binary data-stream. passwords match, a client is granted access to the WLAN. keys for each wireless client. It does not particularly matter exactly where the constellation points are positioned, and in this figure they are shown on the real axis, at 0° and 180°. Wireless networks that use legacy hardware The construction is the same as above for ordinary QPSK. Because the symbols are encoded in the difference in phase between successive samples, this is called All convey data by changing some aspect of a base signal, the A convenient method to represent PSK schemes is on a For determining error-rates mathematically, some definitions will be needed: network SSID, is used to generate unique encryption keys for each The two signal components with their bit assignments are shown the top and the total, combined signal at the bottom. a WLAN Service profile because the other choice, 802.1X authentication, PSK Short for phase-shift keying, a modulation technique used by modems in which different phase angles in the carrier signal are used to represent the binary states of 0 and 1. PSK technique is widely used for wireless LANs, bio-metric, contactless operations, along with RFID and Bluetooth communications. This yields the four phases π/4, 3π/4, 5π/4 and 7π/4 as needed. type, additional processing power is required to keep the network The simplest method of PSK, also called biphase modulation, uses two signal phases - 0 degrees and 180 degrees. 555-560). Director: Wi-Fi Protected Access (WPA) and the newer WPA2. Vol. WPA2 standard. MILCOM 2000. Using a technology called TKIP The total signal – the sum of the two components – is shown at the bottom. Differential schemes for other PSK modulations may be devised along similar lines.
It is seen that Bounds on the error rates of various digital modulation schemes can be computed with application of the Differential phase shift keying (DPSK) is a common form of phase modulation that conveys data by changing the phase of the carrier wave. encryption ciphers used to secure the network. The bit-error rates of DBPSK and DQPSK are compared to their non-differential counterparts in the graph to the right.