Sanyo Electric Co., Ltd.

Hera Wireless S.a.

Kyocera Corporation

Ntt Data Sanyo Systems Corporation

Yasuhiro Tanaka

Seigo Nakao

Nobuo Higashida

Akifumi Hirata

Shinichi Yamaguchi

Ken Nakaoka

Kiyoshige Ito

Yoshiyuki Otani

Yuya Tanaka

Toma Watanabe

Nirou Imaoka

Kenichi Muto

Ryuichi Komatsu

Akio Watanabe

Yasuhiro Oribe

A storage unit stores a preamble signal defined in a legacy system and a preamble signal defined in a MIMO system. A monitoring unit in a transmitting apparatus monitors the existence of any communication apparatus which is not compatible with the MIMO system but accepts the legacy system. A channel characteristics acquiring unit derives the characteristics of a radio channel between the transmitting apparatus and a receiving apparatus. A selector selects a packet format based on a monitoring result obtained by the monitoring unit. The selector also selects where to place LTS, based on the characteristics of wireless channel derived by the channel characteristics acquiring unit.

Method and apparatus for transmitting signals

A radio unit and a baseband processing unit perform wireless communications with a plurality of base station apparatuses compatible with a plurality of wireless communication schemes, respectively. A battery remaining amount management unit inspects a remaining amount of battery to be supplied to the radio unit and the like. A control unit controls standby operations that the radio unit and the baseband processing unit are to perform on the plurality of wireless communication schemes, based on the remaining amount of battery inspected by the battery remaining amount management unit. The control unit defines degrees of priority for the plurality of wireless communication schemes, respectively. As the remaining amount of battery becomes low, the control unit sets long a time interval of the standby operation for a base station compatible with a wireless communication scheme having a low degree of priority.

Method for controlling standby operations compatible with a plurality of wireless communication systems and method for performing operations compatible with a plurality of wireless communication systems

Method and apparatus for transmitting signals, and method and apparatus for receiving the signals

A radio apparatus communicates with a plurality of terminal apparatuses by using a packet signal composed of at least one stream. A control unit divides a certain period into a plurality of partial periods and assigns respectively the plurality of partial periods to the plurality of terminal apparatuses by associating the periods with the terminal apparatuses. The control unit also generates a packet signal for use in control and packet signals for use in inquiry. In so doing, the control unit generates the inquiry packet signals for the plurality of respective terminal apparatuses, as a single packet signal. A baseband processing unit and other units transmit the control packet signal and then transmit the inquiry packet signals, and receive packet signals, containing inquiry results, from the plurality of respective terminal apparatuses.

Communication method for transmitting multiple packet signals, and radio apparatus and communication system using the same

Using as a reference a known signal assigned to one of a plurality of streams that constitute a packet signal, a control unit applies a cyclic timing shift to known signals assigned to the other streams so as to produce packet signals which are to be transmitted finally. While varying the amount of timing shift, the control unit produces a plurality of packet signals and appends an identification number, with which to uniquely identify each of the plurality of produced packet signals, to each of the packet signals. A baseband processing unit and the like transmit, as a transmission rate inquiry signal, a packet signal constituted by a plurality of streams where the amounts of timing shift are made to differ, and receive a response signal to which the same identification number is appended for the inquiry signal.

Radio apparatus and communication system utilizing the same

In a combination of control signals on data signals and the data signals where the combination contains data signals to be assigned respectively to a plurality of streams, a control unit assigns a control signal contained in a leading combination and assigns a data signal, contained in the leading combination, to a position posterior to the assigned control signal. The control unit appends a known signal to at least one of the remaining combinations and then assigns sequentially the remaining combinations to a position posterior to the assigned data signal so as to generate packet signals.

Method and apparatus for transmitting signals for multiple input multiple output wireless communication system

A control unit generates packet signals while controlling an interface (IF) unit, a modulation unit and a baseband processing unit. While dividing each packet signal into a plurality of partial periods, the control unit assigns data to at least part of each of the plurality of partial periods and sets the rate of data, for a partial period placed anterior to each packet signal, higher than that for a partial period placed posterior to the each packet signal. The IF unit, the modulation unit and the baseband processing unit transmit the packet signals thus generated.

Radio apparatus and communication system

A data rate is to be determined depending on circumstances. A control unit () transmits, at a predetermined frequency, a request signal by which to supply information on a data rate to a targeted radio apparatus compatible with a variable data rate. The control unit () receives rate information from the targeted radio apparatus. The control unit () sets a data rate used in the case of transmitting data, based on the information on a data rate contained in the rate information. The control unit () identifies the reliability level of the data rate contained in the rate information. And when the reliability level is low, the control unit () lowers the frequency at which the rate request signal is transmitted.

Radio apparatus

A control unit aggregates packets which are to be sent to one or more terminal apparatuses, and produces aggregated packets. The control unit divides a certain period into a plurality of partial periods, allots each of the plurality of partial periods to any of the plurality of terminal apparatuses and produces a control signal with which to convey an assignment condition to the terminal apparatus. In the case of an aggregated packet where the packets for the plurality of terminals are aggregated, a baseband processing unit and the like transmit the aggregated packet together with the control signal to the plurality of terminal apparatuses. In the case of an aggregated packet where the packets for a single terminal are aggregated, they transmit the aggregated packet to the plurality of terminal apparatuses, without sending the control signal.

Radio apparatus and communication system using the same

An examining unit examines the radio wave environments on at least one of a plurality of frequency channels usable in communications. Based on a result of examination by the examining unit, a selector selects a frequency channel to be used for communications. While using the channel selected by the selector, an execution unit transmits signals from a plurality of antennas to a terminal apparatus and performs calibration on the plurality of antennas by receiving signals from the terminal apparatus via the plurality of antennas.

Calibration method, and base station apparatus, terminal apparatus and radio apparatus utilizing the same

A control unit estimates the time required from when signals are transmitted respectively to a plurality of terminal apparatuses to when responses from them are received. In a plurality of partial periods, partial periods for receiving signals continue after partial periods for transmitting the signals continue, and the order of terminal apparatuses assigned in the partial periods for receiving signals are defined in the order of terminal apparatuses assigned in the partial periods for transmitting signals, and the control unit assigns a terminal apparatus, whose estimated required time is longer, to an early partial period in a series of partial periods for transmitting signals. A radio unit and the like perform communication with the plurality of terminal apparatuses to which the respective plurality of partial periods have been assigned.

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Aichi, Japan

Yasuhiro Tanaka