The spectrum database is implemented to store the information
of available channel bands for the CRCN users. Essentially, these channel bands
are classified into several categories according to the standard IEEE802.22. For
simplicity, this simulator defines two classes for the channel bands. The
channel bands belong to the first class (i.e., Level1) can be occupied by the
CRCN users immediately, once these channel bands are detected as unoccupied by
the primary users. On the contrary, those channel bands which are vacated by
the CRCN users because of the presence of primary users are classified as the
second class (i.e., Level2). These channel bands also need to be sensed by the
CRCN users periodically. After claimed as vacant by the CRCN for a determined
number of times, the channel bands in the second class are upgraded into the
first class. These channel band information are saved in a table called
“Available Channel Bands for CRCN”.
There is another table in the database which is
called “Channel Sensing Report”. This table records the sensing reports from
the secondary users for each channel band. There are only two items in this
table, i.e., the channel index and the channel utilization status. The channel
utilization status indicates if this channel band is occupied by the primary
user (represented by “1”) or not (represented by “0”).
The two tables and their relationship are shown
below:
Available Channel Bands for CRCN |
||
Channel Index * |
Channel Status |
Channel Bandwidth (MHz) |
0 |
Level 1 |
5 |
1 |
Level 2 |
5 |
2 |
Lever 1 |
5 |
3 |
Lever 1 |
5 |
4 |
Lever 1 |
5 |
5 |
Lever 2 |
5 |
|
|
|
Channel Sensing Report |
|
Channel Index * |
Channel Utilization Status |
0 |
1 |
1 |
0 |
2 |
0 |
3 |
0 |
4 |
1 |
5 |
1 |
|
|
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