Final report on link level and system level channel models - Winner

WINNER D5.4 v. 1.4
figure represents one period of the transmit/receive signal. Synchronous switching at the Rx and Tx is
required in order to clearly assign the received signal periods to any input-output combination of the
channel matrix. Timing and switching frame synchronization is established during an initial
synchronization process prior to measurement data recording and must be maintained over the complete
measurement time even in the case of remote operation of Tx and Rx. This is accomplished by rubidium
reference oscillators at both Rx and Tx.
M Tx
M Rx
Tx
Rx
Tx switching sequence
Rx switching sequence
Tx
channel
Rx
1
2
3
1
2
3
4
t p = T x Signal period = τ max = maximum path excess delay
time
t s = τ max 2 M Tx M Rx = total snapshot time duration
Figure 5.4: MIMO sounder switching time frame.
5.1.2.3 KTH measurement system
The KTH measurement system is based on four parallel transmitters tuned to slightly different
frequencies. Figure 5.5 presents a block diagram of the transmitter.
∑
Reference
Antenna
TX module 1
TX module 2
splitter
splitter
TX antenna 1
TX antenna 2
Laptop PC
TX module 3
splitter
TX antenna 3
TX module 4
splitter
TX antenna 4
Figure 5.5: Block diagram of the transmitter chains.
Each base station contains four parallel receiver chains as shown in Figure 5.6. The combined RF signal
from each vertical array is input to its corresponding RX module. The output signal of the RX module is
fed to an analog-to-digital converter (ADC). The ADC collects 40000 samples from each signal chain per
second and writes the sampled data to the hard disk of a computer. These raw data samples are processed
and analyzed later by software in an off-line fashion.
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