*** Network ***

Layer 0 :                 1
                          |
                        -----
                       |     |
Layer 1 :              10   11
                       |     |
                 -------------------
                 |     |     |     |
Layer 2 :        20    21    22  ...  29
                 |     |     |     |
                 -------------------
                 |     |     |     |
Layer 3 :        30    31    32  ...  39
                 |     |     |     |
                 -------------------
                 |     |     |     |
Layer 4 :        40    41    42  ...  49
                 |     |     |     |
                 -------------------
                 |     |     |     |
Layer 5 :        50    51    52  ...  59
                 |     |     |     |
                 -------------------
                 |     |
Layer 6 :        60    61 ..........


Node1(Sink) sends a message to other nodes in sequence every about 3 sec.
The other nodes send messages to Sink every about 3 sec.

Each node can communicate with upper, lower and same layer nodes only.
(We blocked the communication in MAC layer by inserting additional codes)
