Wireless Communication

1.

Wireless Communication

2.

Outline:
1. Wireless Communication & Diversity
2. Broadband Wireless Communication Channel
3. CDMA – Code Division Multiple Access
4. OFDM – Orthogonal Frequency Division Multiplexing
5. MIMO – Multiple Input Multiple Output
Communication Systems
6. UWB – Ultra Wideband Systems
7. 3G/4G – WCDNA, HSDPA, LTE, WiMAX

3.

Prerequisites:
1.Probability and Random Processes
2.Digital Communication
3.Introduction to Wireless Systems
4.Linear Algebra

4.

Wireless Commnication:
- Scatters
Ex: Trees
Cars
Buildings
LOS
- Multipath
Propagation
Environment
MS
BS
LOS – Line of Sight
NLOS – Non-line of sight

5.

Wireless Communication:
Constructive or Destructive Interference
x (t)
Transmitted
signal
h (t)
y (t)
Rx
Tx
Wireless
channel
Received
signal

6.

0th Path
LOS
a0δ(t-τ 0)
1
0
alternation
factor
st
1
Path
Non-Line
of sight
MS
BS
Delay
a1δ(t-τ 1)
a2δ(t-τ 2)
..
..
aL-1δ(t-τ L-1)

7.

Multipath Component
..
h(t) = a0δ(t-τ 0) + a1δ(t-τ 1) + .+ aL-1δ(t-τ L-1) =
impulse
Response
of
Wireless
Channel
L-1
=
i=0
a i δ(t-τ i )

8.

Wireless Signal
S(t)=Re{Sb(t)e
Baseband-Passband
Representation
j2xfct
}
Complex Baseband
Equivalent of
the passband
signal s(t)
fc is the carrier frequency

9.