Patent ID: 7530001
Filing Date: 2009-05-05
Classification: H04L

Abstract:
1. A wireless communications system comprising first and second wireless communications apparatus connectable over a network, wherein said first wireless communications apparatus comprises: a first transmitter/receiver for transmitting packet data including either preamble information and an error detection code or only the preamble information to said second wireless communications apparatus, and receiving data transmitted from said second wireless communications apparatus; a first determination circuit for calculating a first correlation value of the data received by said first transmitter/receiver with first predetermined preamble information, and determining whether or not the first correlation value is equal to or larger than a first threshold value; and a controller for controlling said first transmitter/receiver to retransmit the packet data including the preamble information and the error detection code when the determination circuit fails to determine that the correlation value is equal to or larger than the first threshold value in a first predetermined period of time after having transmitted the packet data including the preamble information and the error detection code, said second wireless communications apparatus comprising: a second transmitter/receiver for transmitting packet data including either the preamble information and the error detection code or only the preamble information to said first wireless communications apparatus, and receiving data transmitted from said first wireless communications apparatus; a second determination circuit for calculating a second correlation value of the data received by said second transmitter/receiver with a second predetermined preamble information, and determining whether or not the second correlation value is equal to or larger than a second threshold value; and a second controller for controlling said second transmitter/receiver to retransmit the packet data including the preamble information and the error detection code when said second determination circuit fails to determine that the second correlation value is equal to or larger than the second threshold value in the second predetermined period of time after having transmitted the packet data including the preamble information and the error detection code.