Nippon Telegraph and Telephone Corporation

Tajima Incorporated

Tokyo Ertec Co., Ltd.

Satoru Aikawa

Shinya Otsuki

Kazuyoshi Saito

Tomoaki Kumagai

Kengo Nagata

Atsushi Ohta

Yasuhiko Inoue

Akinori Hirukawa

Yoichi Saito

Yuji Nakayama

Eiichi Tajima

Hitoshi Takanashi

Norihiro Inagaki

Satoshi Kurosaki

Shigeru Tasaka

Masahiko Itoh

Yoji Inoue

Yasuhisa Nakamura

Kengo Nataga

When a transmission rate of each of lines that transmit data simultaneously between two STAs by using a plurality of radio channels and/or MIMO can be set independently, one data frame is fragmented in accordance with the transmission rates of the respective lines so as to generate a plurality of data packets having the same packet time length and data sizes equal to or smaller than a maximum data size. Those data packets are transmitted simultaneously by using a plurality of radio channels, or one radio channel and MIMO, or a plurality of radio channels and MIMO.

Wireless packet communication method

In retransmission processing due to a failure of transmission of data packets, a plurality of data packets are simultaneously transmitted between two STAs by utilizing multiple wireless channels and MIMO, and the number of idle channels and the number of retransmission packets are compared. Then, when both of the numbers are different or only when the number of idle channels is larger than the number of retransmission packets, the retransmission packets are reconstructed according to the number of idle channels, and the reconstructed retransmission packets are simultaneously transmitted by using the idle channels.

Wireless packet communication method and wireless packet communication apparatus

Data packets are transmitted between two STAs capable of using plural radio channels and MIMO together, by using idle channels and MIMO. When at least one idle channel has been detected, plural data packets are generated in the same number as the sum of MIMO numbers of the respective idle channels, in which the data packets are generated from one or plural data frames, and plural data packets having the same packet time length are transmitted simultaneously between the two STAs by using the idle channels and MIMO.

A plurality of types of available transmission rates to be used for transmission of data packets are individually managed for each receiver terminal. When there are a plurality of data packets to be transmitted onto a transmission buffer and when it is possible to transmit said plurality of data packets simultaneously, the packet sizes representative of the data amounts of the respective data packets are referred to as well as the transmission rates of the respective data packets associated with the receiver terminals. The packet time lengths (transmission times) defined by the packet sizes and transmission rates are checked for the respective data packets. A plurality of data packets whose packet time lengths are approximately equal to each other are selected regardless of their receiver terminals. The transmissions of the plurality of selected data packets are commenced simultaneously by use of a plurality of radio channels.

For data packet transmission in special format generated by connecting or patching data frames, a request packet and reply packet receivable only by STAs supporting the special format are transmitted/received before the data packet transmission, to check and manage the STA supporting the special format. Based on management information in own station, the data packet is transmitted in the special or standard format according to a receive-side STA. For generating plural data packets in special format in which plural data frames are patched, the plural data frames having subheaders added are connected and divided to data blocks. A main header including information necessary to restore patched data frames are added to each data block, and a control information field and a frame check field of a data packet are added before and after the data block having the main header added thereto, respectively, to generate data packets.

Wireless packet communication method and apparatus

A transmit-side STA transmits a wireless packet using a wireless channel which has been determined to be idle by both a physical carrier sense for determining based on received power whether the wireless channel is busy or idle and a virtual carrier sense for determining the wireless channel to be busy during set transmission inhibition time. At this time, the transmit-side STA sets transmission time used for the virtual carrier sense to a paired wireless channel which is affected by leakage from a transmitting wireless channel. This allows for setting transmission inhibition time to a paired wireless channel even when the paired wireless channel cannot successfully receive due to the effect caused by leakage from the transmitting wireless channel.

A plurality of data packets that contain sequence numbers, respectively, are transmitted simultaneously between two STAs by using a wireless channel and MIMO. An STA receiving the plurality of data packets transmitted simultaneously by using MIMO generates a single ACK packet containing information that corresponds to a sequence number of each data packet successfully received, and transmits the single ACK packet to a transmit-side STA without using MIMO. Thus, a ratio of successful ACK packet receptions to total receptions can be increased. An effect of improving throughput achieved by simultaneous transmission can also be ensured.

In a wireless packet communication method for transmitting a plurality of wireless packets simultaneously by using multiple wireless channels determined to be idle by carrier sense, a wireless channel determined to be idle and MIMO, or the multiple wireless channel and the MIMO, a mandatory channel that is always used for transmission is set. The wireless packets are transmitted by using the wireless channel(s) including the mandatory channel only when the mandatory channel is idle. That is, in case of transmitting a plurality of wireless packets simultaneously, transmission is performed by using the wireless channel(s) including the mandatory channel, and transmission is not performed when the mandatory channel is not idle.

A plastic as a material to be treated and an additive such as unsaturated fatty acid oil are mixed, and the mixture is heated in a pyrolysis tank at a temperature of 300&#xb0; C. to 450&#xb0; C. by a heating member to thereby thermally decompose the mixture. A gas component produced during the heating process is then removed and a pyrolysate is thus produced.

Method and system for pyrolyzing plastic and pyrolysate product

In a wireless access system which uses the sector antenna of a radio base station to transmit an access channel to and receive an access channel from a radio terminal in each frame, and which switches the sector at each frame, the sector ID s is set in a specific functional relation to the access channel ID a, and a radio terminal which communicates with a radio base station transmits and receives in accordance with the access channel ID a without knowing the sector ID s.

Wireless access system

A self-crosslinking composition contains: (a) an oil having an unsaturated fatty acid or an ester of an unsaturated fatty acid as one of its components, (b) a drier, and (c) a polymer or an elastomer that is capable of crosslinking in the absence of a peroxide. A forming (such as a floor tile, a linoleum long floor material, a wall material and a water-proof sheet) may be manufactured by forming and curing the self crosslinking composition and then adding a filler. Since the self-crosslinking composition is capable of crosslinking without using peroxide, the crosslinking reaction is easily conducted without using special equipment to reject air. The composition has a number of advantages over crosslinking methods that use peroxide, including decreased scorch generation, decreased permanent compressive strain, and superior heat resistance and anti-aging resistance. The composition is free from pollution of sulfur and metal and generates no harmful gas during waste incineration. Furthermore, the composition is capable of being blended, formed, and crosslinked under milder conditions than that of conventional methods that use peroxide. The formings show particularly high abrasion resistance, cigarette-proof properties, anti-stain properties, low charge voltages, and high stiffness. Therefore, the formings are suitable for floor tile and linoleum floor material.

Self-crosslinking composition, forming obtained from the composition,

In Trellis coded modulation system in which an input digital signal in parallel form is encoded by a convolutional encoder which adds an additional bit to the input digital signal for error correction purpose, and a mapping circuit designated amplitude and phase for each symbol for QAM signal, the number of parallel bits at output of said convolutional encoder is the same as the number of parallel bits of an input digital signal. An input digital signal is first rate converted so that m+n bits in every T period is converted to m bits in every T' period, where T'=(m/(m+n)).T. The convolutional encoder adds n number of bits so that the total number of parallel bits is m+n, which is applied to the mapping circuit. In a receive side, a received signal having m+n bits in every T' period is decoded through an error correction decoder which provides m bits in every T' period, then, the decoded signal is rate converted to m+n bits in every T period. So, the number of parallel bits does not increase in spite of convolutional encoding, but a transmission rate is a little increased. The coding gain in the present invention is improved since the number of levels of the QAM signal is not increased although the bandwidth of the signal is a little increased because of the higher clock rate.

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Kanagawa, Japan

Satoru Aikawa