Access Time Analysis of MCPTT Off-Network Mode over LTE

Table 9

Impact of parameters configuration on MCPTT access time.

Parameter	Small	Big
	(i) Shorter access time; (ii) More overhead;	(i) Longer access time; (ii) Less overhead;
	(i) Faster retransmissions of Call Probe; (ii) More unnecessary retransmissions of Call Probe (e.g., with 3GPP default configuration) are likely;	(i) Reduced unnecessary retransmissions of Call Probe; (ii) Necessary Call Probe retransmission may be slowed down;
	(i) Reduced nominal maximum and average access time; (ii) The call merge procedure is more likely to be triggered (e.g., with 3GPP default configuration), and result in increased effective maximum and average access time;	(i) Nominal maximum and average access time may be larger; (ii) Reduced unnecessary call merge procedure triggering, and thus reduced effective maximum and average access time;
& ()	(i) Faster determination of idle floor; (ii) The “multiple floor arbitrators situation” is more likely to occur (e.g., with 3GPP default configuration); (iii) More unnecessary retransmissions of Floor Request (e.g., with 3GPP default configuration) are likely.	(i) Slower determination of idle floor; (ii) The “multiple floor arbitrators situation” can be reduced (C201T201); (iii) Reduced unnecessary retransmissions of Floor Request.