Advantages and disadvantages of QPSK (2024)

FAQs

Advantages and disadvantages of QPSK? ›

Advantages and Disadvantages

Some advantages of using QPSK over BPSK in satellite communication systems include: Higher data rates: QPSK is able to transmit data at a higher rate than BPSK, as it can encode two bits of information per symbol, rather than just one.

QPSK has the very significant advantage that it can be used to double the data rate over the same bandwidth, or half the bandwidth for the same data rate. Further, as the number of signal states increases from 4 (quadrature) to N-ary, the trade-off can be furthered.

Disadvantages of BPSK

Some of the disadvantages of Binary Phase Shift Keying process includes: Low Data Sending Rate: However when it comes to data transmission speed, BPSK has limitations as it can only send one piece of data at a time.

Conclusion : In summary, FSK modulation offers advantages in terms of noise immunity, simplicity of demodulation, and suitability for noisy environments. However, it has limitations in terms of spectral efficiency and may not be the best choice for high-data-rate or mobile communication applications.

The phase of the carrier wave can be modified in one of two ways with BPSK modulation, the advantage of QPSK is that two bits can be represented per symbol unlike BPSK, which can only represent one bit per symbol.

In the quadrature phase-shift keying (QPSK) scheme, two bits are grouped at a time, and mapped into one of the four possible signals. As with BPSK ( M = 2 ) , the information in QPSK ( M = 4 ) is contained in the carrier phase (i.e., the phase of the carrier takes on one of four equally-spaced values).

One significant advantage of QAM over QPSK is its ability to transmit more bits per symbol, leading to higher data rates. QAM schemes can represent multiple bits in each symbol, allowing for increased throughput within the same bandwidth.

QPSK is more efficient than BPSK because it has more bits per symbol. But in all cases efficiency is also a function of the noise of the channel as well. Generally, it's the SYMBOL rate, not the bit rate, that determines BW. BPSK is one bit per symbol.

In BPSK modulation, each carrier carries one single bit hence symbol rate is equal to bit rate. BPSK is considered to be power efficient and not bandwidth efficient.

Is QPSK the same as 4 QAM? ›

These are at the corner of a square (a square lattice), at angles π/4, 3π/4, 5π/4 and 7π/4 to the real axis. You will see this signal constellation later in the experiment. The above has described digital-QAM or QPSK. This signal is also called 4-PSK or 4-QAM.

The main difference between BPSK and QPSK is the number of bits that are transmitted in each symbol. BPSK transmits one bit per symbol, while QPSK transmits two bits per symbol. This means that QPSK is more bandwidth-efficient than BPSK, as it can transmit twice as much data in the same amount of time.

QPSK can transmit approximately 1.4 information bits/Hz of bandwidth, while BPSK can transmit only about 0.7 information bits/Hz of bandwidth.

The constellation diagram of QAM shows that the distance between each combination is constant for any order. PSK has a smaller distance; thus, it is very rational for QAM to perform better than PSK for the higher-order as 16-QAM, 64-QAM, and 256-QAM.

Following are the disadvantages of FSK:

➨It uses larger bandwidth compare to other modulation techniques such as ASK and PSK. Hence it is not bandwidth efficient. ➨The BER (Bit Error Rate) performance in AWGN channel is worse compare to PSK modulation.

Disadvantages of QAM:

QAM requires coherent demodulation with the same phase and frequency. As QAM uses the amplitude component of the signal to represent binary data, linearity needs to be maintained; hence linear amplifier is required which consumes more power.

It is obvious from table 1, that the QPSK scheme (ie, M = 4 ) offers the best tradeoff between power (Sav) and bandwidth requirements. For this reason, QPSK modulation is used in this particular design. In addition, it is widely used in practice.

Since in BPSK, only one bit per symbol is transmitted. Since in QPSK, only two bits per symbol are transmitted. Therefore, we can say that the data rate of QPSK is twice as that of BPSK for the same symbol rate.