In CSMA/CD Binary Exponential Backoff, what is the maximum value of collision counter c used to determine the backoff range [0, $2^c - 1$]?
In IEEE 802.3 CSMA/CD, the exponent c caps at 10 (i.e. max range [0, $2^10 - 1$] = [0, 1023]). After 16 total collisions, the frame is aborted.
If the CRC generator polynomial is G(x) = $x^4 + x + 1$, how many zero bits must be appended to the data payload before binary division?
Degree of polynomial G(x) = $x^4 + x + 1$ is 4. The number of appended zeros equals the degree of the generator polynomial, which is 4.
Data bits = 100100, CRC Generator polynomial G(x) = $x^3 + 1$ (binary 1001). What is the remainder (checksum) appended to the message?
Append 3 zeros: 100100000. Modulo-2 division by 1001 gives remainder 001, so the CRC bits are 001.
To GUARANTEE detection of up to d bit errors in any codeword, what must be the minimum Hamming distance ($d_{min}$) between valid codewords?
For error detection of up to d errors: $d_{min}$ >= d + 1. For error correction of up to t errors: $d_{min}$ >= 2t + 1.
To GUARANTEE correction of up to t bit errors in any codeword, what is the required minimum Hamming distance ($d_{min}$)?
Minimum Hamming distance for correcting t errors is $d_{min}$ >= 2t + 1.