1 When you increase the data rate of a communications system

1. When you increase the data rate of a communications system, typically, the error rate increases. Explain why. (1 point) 2. What is the purpose of using RTS packets? Why RTS packets are typically very small? (0.75 point) . Fragmentation is splitting a big packet into several smaller chunks for transmission over the wireless medium. Please list two advantages and one disadvantage of using fragmentation. (0.75 point)

Solution

1).
Bit error rate, BER is a key parameter that is used in asses the systems that transmit digital data over the network.
bit error rate=no.of errors / total n no.of bits sent..
if the channel between the sender and receiver is good and the signal to noise ratio is high, then the bit error rate will be very small.

reduce bandwidth: Another approach that can be adopted to reduce the bit error rate is to reduce the bandwidth. Lower levels of noise will be received and therefore the signal to noise ratio will improve. Again this results in a reduction of the data throughput attainable.

if we increase the bandwidth then no.of bits per second increases as the formula said that no.of sending bits increases then error rate may increases.

2).
RTS:request to send:
it is a packet that it is used to tell to the reciever to strart the transmission of data
it has five fields:
Frame Control
Duration
Receiver Address
Transmitter Address
FCS

rts packets are small in size because these are only contains the threshold is 0–2347 octets.
so the size of the packets are small.

3).
advantages:
1. save memory if segments are very small and should not be combined into one page.
2.less overheads.
3.parallelism:by using fragments we can able to work on different framgments at the same time.
4.increased efficiency
disadvantages:
1.memory management algorithms are very costly.
2.finds memory area big enough.
3.performance decrease:because fragments at different areas can be collected for processing.
4.integrity.