Patent ID: 8379744
Filing Date: 2013-02-19
Classification: H04B,H04L

Abstract:
1. A radio terminal apparatus comprising: a receiver configured to receive a packet signal formed by a plurality of streams modulating a plurality of subcarriers in predetermined bandwidths, said packet signal being in either a first packet format or a second packet format, the first packet format including first legacy known signals for a first radio communication system different from a second radio communication system, second legacy known signals for the first radio communication system, and first MIMO known signals for the second radio communication system, the first legacy known signals, the second legacy known signals, and the first MIMO known signals being arranged in that order, the second packet format including second MIMO known signals for the second radio communication system and the first MIMO known signals, the second MIMO known signals and the first MIMO known signals being arranged in that order, no first and second legacy known signals being included in the second packet format; an ACG (auto gain control) estimation module configured for performing ACG estimation based on said first legacy known signals or said second MIMO known signals; a channel estimation module configured for performing channel estimation based on said second legacy known signals or said first MIMO known signals; wherein subcarriers for the first MIMO known signals have a bandwidth which has the same center frequency as that of subcarriers for the second legacy known signals and which is broader than that of subcarriers for the second legacy known signals, wherein said first and second legacy known signals and said first and second MIMO known signals are generated by execution of a cyclic time shifting with shift amounts being varied across the plurality of streams, a maximum absolute shift amount among absolute shift amounts for the first MIMO known signals in the plurality of streams is greater than absolute shift amounts for the second legacy known signals in the plurality of streams, and a maximum absolute shift amount among absolute shift amounts for the second MIMO known signals in the plurality of streams is greater than absolute shift amounts for the first legacy known signals in the plurality of streams.