A comparison between the proposed BwT protocol and the presented protocols in Section 2.2, BT , FTTP , OBTT , and QwT , is presented here.
BwT, in addition, attaches W represented with [log.sub.2] W +1 bits; and QwT uses the length of the query on every slot plus the corresponding W bits.
Although QwT also uses the window, the excessive number of bits demanded by the reader transmitting queries causes a higher increase in the total number of bits than that of the BwT, decreasing also the throughput of the system.
QwT shows a high increase when there are a few tags on the range of the reader's antenna and BT shows the worst results of the comparison.
As the bit window technique modifies the number of tag transmitting bits per slot, Figure 6(b) shows the improvement caused by the window in QwT and BwT as the least tag bit transmitting protocols, quite the opposite of BT.