US 7,577,447 B2
Communication system and communication terminal apparatus with changeable transmission/reception periods
Katsutoshi Itoh, Tokyo (Japan); Mitsuyoshi Yasuda, Tokyo (Japan); Makoto Natori, Saitama (Japan); Osamu Yoshimura, Kanagawa (Japan); Minoru Yokoshi, Tokyo (Japan); and Takeshi Itagaki, Tokyo (Japan)
Assigned to Sony Ericsson Mobile Communications Japan, Inc., Tokyo (Japan)
Filed on Jun. 28, 2005, as Appl. No. 11/168,666.
Claims priority of application No. P2004-195062 (JP), filed on Jun. 30, 2004.
Prior Publication US 2006/0019678 A1, Jan. 26, 2006
Int. Cl. H04W 24/00 (2009.01)
U.S. Cl. 455—456.3  [455/41.2; 455/420; 455/421; 455/567; 455/574; 370/468; 707/10] 6 Claims
OG exemplary drawing
 
1. A communication system comprising:
a communication terminal apparatus; and
a wireless key apparatus capable of a wireless communication with the communication terminal apparatus by a predetermined wireless communication system and limits a function of said communication terminal apparatus in response to a communication state between said communication terminal apparatus and said wireless key apparatus, wherein
said predetermined wireless communication system is a system in which one of two apparatuses carrying out a communication each other becomes a master and the other one becomes a slave such that a signal from the master is detected by the slave so as to carry out a wireless connection between the two apparatuses;
each of said communication terminal apparatus and said wireless key apparatus comprises
communication means for carrying out a wireless communication by said predetermined wireless communication system, and
control means for controlling the communication state in said communication means;
when the wireless communication state between said communication terminal apparatus and said wireless key apparatus is a non-connection state, the communication means on the side which becomes said master decreases a transmission period in a plurality of steps in response to the non-connection time period and transmits a signal asking for a response from said slave intermittently; and
the communication means on the side which becomes said slave decreases a reception period in a plurality of steps in response to the non-connection period and carries out a reception for searching for the signal from said master intermittently.