# Thread: Wireless Communication HELP Needed to Solve Paper in 10hrs

1. ## Wireless Communication HELP Needed to Solve Paper in 10hrs

fellows i am a masters student and i have been given an assignment which is due in 10hrs. the subject is Mobile / wireless communication. please is any one interested in helping ?

i am pasting my entire paper below, please help me solve it and send me solutions for it. thank you

[b]• Q1 (5 pt) Consider a GSM system operating at 30 dB SNR.
a. What is the maximum theoretic data capacity? (2 pt)
b. Does this GSM system utilize the above calculated data rate? Explain your answer. (3 pt)

• Q2 (12 pt) Assume that the binary bit stream {1000110110} is to be modulated using BPSK with a data rate of 1 Mbps.
a. What is the first-zero crossing BW of the RF spectrum if simple rectangular pulses are used? (3 pt)
b. What is the absolute BW of the RF spectrum if raised cosine roll-off pulses are used with ? = 1/3? (3 pt)
c. Does the absolute BW in part (b) capture all the energy of the signal? (3 pt)
d. If the receiver experiences 1 ?s timing jitter, will the adjacent symbols cause ISI when raised cosine roll-off pulses are used? (3 pt)

• Q3 (9 pt) An 18,000-feet twisted-pair telephone line has a usable BW of 750 KHz. Data is modulated over this line using QPSK with simple rectangular pulses.
a. What is the maximum bit rate that can be supported over this line such that the first-zero crossing BW consumes the entire usable BW? (3 pt)
b. What will happen if the length of this telephone line is increased to 20,000 feet? (3 pt)
c. What will happen if the 18,000-feet twisted-pair line is replaced with a coaxial cable of the same length? (3 pt)
• Q4 (18 pt) Consider the transmitter and receiver system shown below, which is fed by two independent sources of data m1(t) and m2(t).

a. Express the transmitted signal, s(t), as a function of m1(t) and m2(t). (3 pt)
b. What type of modulation is applied to each data source? (3 pt)
c. Express the two received signals, x(t) and y(t). (3 pt)
d. What is the total aggregate bit rate of this system if both m1(t) and m2(t) are running with a bit rate of 1 Mbps? (3 pt)
e. Consider the case where the front end of the transmitter is replaced with a TDM switch running at 2 Mbps and alternating between m1(t) and m2(t) before multiplying them with the two quadrature carriers. What type of modulation is used in this new system? What is the total aggregate bit rate? (6 pt)

• Q5 (12 pt) A base-band binary message with a bit rate of 100 kbps is modulated using BPSK.
a. What is the range of the maximum excess delay values required to make the received signal flat fading? (3 pt)
b. If the modulated carrier frequency is 2.4 GHz, what is the coherence time of the channel with respect to a car with a speed of 80 Km/h? (3 pt)
c. For part (b), is the channel fast or slow fading?
d. Based on your answer in part (b), how many bits can be sent while the channel appears static to the transmitter? (3 pt)

2. For heavens sake you are a graduate student you should know better than asking us for last minute help on assessed work, is that how you passed you first degree.

Also you are unlikely to get much help here on coms systems.

CB