Deriving Bit Error Rates for different diveristy tecniques

In summary, for the given problem, the main task is to derive SNR values for different diversity techniques (selection combining, equal gain combining, maximal ratio combining) using the normal distribution over Rayleigh fading. For non-coherent BPSK, the bit error rate (BER) was found in terms of SNR (gamma). Now, the goal is to find the BER for the different diversity techniques, which involves a sum and a double integral. The sum is -BER_SC/EGC/MRC and the double integral term is yet to be determined. The SNR values for the respective diversity techniques are used in the sum. However, it is unclear what to integrate with for the double integral term.
  • #1
Ian_Brooks
129
0

Homework Statement



Using the normal distribution for different modulation techniques over rayleigh fading , we have to derive SNR values for different Diversity techniques such as selection combining, Equal Gain Combining and Maximal Ratio Combining.

Now for Non-coherent BPSK I have to derive the Bit Error Rate for different diversity techniques.

I have the Probability of the Bit Error Rate - i need to find how I can find the Bit Error Rate from this. Apparently it involves a sum of another term and then a double integral that would give us the BER.

Can someone point me in the right direction in finding this so called sum and what I have to integrate it with? What would I be integrating the second term by for the double integral, as It can't be Signal To Noise Ration (SNR) of the signal.

Homework Equations



The Probability of a Bit Error Rate was found in terms of SNR (gamma).

The Attempt at a Solution



Too much to type up here.
 
Physics news on Phys.org
  • #2
The BER was found in terms of gamma (SNR) for Non-coherent BPSK.BER = 1/2 * erfc(sqrt(gamma/2)) + 1/2 * exp(-gamma) * erfc(sqrt(gamma/2 + 1))Now for different Diversity Techniques, we have to derive the SNR values for different Diversity techniques such as selection combining, Equal Gain Combining and Maximal Ratio Combining. For Selection Combining,SNR_SC = SNR_1 + SNR_2 + ... SNR_N For Equal Gain CombiningSNR_EGC = N * SNR_1For Maximal Ratio CombiningSNR_MRC = N * max(SNR_1, SNR_2, ... SNR_N)Now I have to find the Bit Error Rate for the different Diversity Techniques, which involves another sum and a double integral. The sum is - BER_SC/EGC/MRC = 1/2 * erfc(sqrt(gamma_SC/EGC/MRC/2)) + 1/2 * exp(-gamma_SC/EGC/MRC) * erfc(sqrt(gamma_SC/EGC/MRC/2 + 1))Where gamma_SC/EGC/MRC are the SNR values for the respective Diversity Techniques. Now I have to find the double integral term. I don't understand how to go about this. How do I know what to integrate with? Thanks.
 
  • #3


I would suggest starting by researching the equations and methods for deriving Bit Error Rates for different diversity techniques. This may involve looking into the theory behind these techniques, as well as previous studies and experiments that have been conducted on them. You can also consult textbooks or research papers on the topic to gain a better understanding of the equations and methods involved.

Once you have a good understanding of the theory and equations, you can then start working on deriving the Bit Error Rates for the different diversity techniques. This may involve using mathematical tools such as integration and summation to solve the equations and obtain the desired results. It is important to carefully follow the steps and assumptions made in the derivation to ensure accuracy and validity of the results.

In terms of the second term and double integral mentioned in the content, it is likely that you would be integrating with respect to the fading distribution of the channel. This could be a Rayleigh or Rician distribution, depending on the specific scenario being studied. Again, it is important to carefully follow the steps and assumptions made in the derivation to ensure accuracy.

Lastly, it may be helpful to consult with a supervisor or colleague who has experience in this area, as they may be able to provide guidance and assistance in the derivation process. Good luck!
 

1. What is the purpose of deriving bit error rates for different diversity techniques?

The purpose of deriving bit error rates is to evaluate the performance of different diversity techniques in communication systems. It helps in determining the effectiveness of these techniques in improving the reliability of the system by reducing the bit error rate.

2. What are the different diversity techniques used in communication systems?

Some of the commonly used diversity techniques include spatial diversity, temporal diversity, frequency diversity, and polarization diversity. These techniques involve using multiple antennas, time slots, frequencies, or polarizations to transmit the same information, thereby improving the signal quality and reducing the bit error rate.

3. How is the bit error rate calculated for different diversity techniques?

The bit error rate is calculated by comparing the received signal with the transmitted signal and counting the number of bit errors. This process is repeated for multiple transmissions, and the average bit error rate is then calculated. For different diversity techniques, the bit error rate is calculated by considering the specific characteristics and parameters of each technique.

4. What factors can affect the bit error rate for different diversity techniques?

The bit error rate can be affected by various factors such as the signal-to-noise ratio, the number of diversity branches, the quality of the channel, and the modulation scheme used. These factors can impact the performance of different diversity techniques and their ability to reduce the bit error rate.

5. How can the derived bit error rates be used in practical applications?

The derived bit error rates can be used to compare the performance of different diversity techniques and determine the most suitable technique for a particular communication system. It can also be used to optimize the parameters of the diversity techniques and improve the overall system performance. Additionally, the bit error rates can be used to estimate the error probability and design error correction coding schemes for reliable communication.

Similar threads

Replies
9
Views
1K
  • General Math
Replies
31
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
23
Views
2K
Replies
3
Views
221
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
6K
Back
Top