摘要:
There are disclosed a random access method for establishing an individual channel between a radio communication terminal device and a base station device in a short time and a radio communication terminal device executing the random access method. In this device, in step ST320, a RACH sub-channel allocation unit (211) allocates a transmission packet inputted from a replication unit (202) to an arbitrary sub-carrier at the RACH arbitrary time slot at random. In step ST330, an allocation unit (210) judges whether an overlap is generated in the allocation result obtained by the RACH sub-channel allocation unit (211). When the allocation unit (210) judges that an overlap is generated in the allocation result, the allocation unit (210) causes one of the RACH sub-channel allocation units (211) which has caused the overlap to again perform allocation of step ST320. On the other hand, when judgment is made that no overlap is generated in the allocation result, step ST340 is executed.
摘要:
A multicarrier communication method and a multicarrier communication apparatus used for the method for adjusting the arrangement in code block units according to the actual reception state of the multicarrier signal, when arranging code blocks generated through error correcting coding processing not only in the time axis direction but also in the frequency axis direction in order to improve an error correction rate of a multicarrier signal. The method according to the present invention includes a coding processing step of carrying out error correcting coding processing on a multicarrier signal, a transmission step of transmitting the multicarrier signal subjected to the error correcting coding processing, a reception step of receiving the multicarrier signal transmitted, an analysis step of analyzing a reception state based on the multicarrier signal received and an arrangement adjusting step of adjusting the arrangement of code blocks generated through the error correcting coding processing according to the analysis result in the analysis step.
摘要:
Based on the determination of a transmission destination determination section 106, a data selector 151 selects only transmit data for the corresponding communication terminal apparatus. An adaptive modulation section 153 modulates the output signal from the data selector 151 using the modulation method indicated by a modulation method determination section 152. A spreading section 154 spreads the output signal from the adaptive modulation section 153 and outputs the resulting signal to a code multiplexer 158. A dedicated pilot signal generator 155 generates a dedicated pilot signal. A modulation section 156 modulates the dedicated pilot signal. A spreading section 157 spreads the output signal from the modulation section 156 and outputs the resulting signal to the code multiplexer 158. The code multiplexer 158 performs code multiplexing of the output signal from the adaptive spreading section 154 and the output signal from the spreading section 157 and outputs the resulting signal to a time multiplexer 162. By this means it is possible to maintain data-part reception quality when performing high-speed downlink packet transmission even when phase changes are sudden.
摘要:
A selector 301 select one a directional signal corresponding to a group to which a transmission signal belongs on a path-by-path basis. A despreader 302 provides despreading to an output signal of the selector 301. A RAKE combiner 305 provides RAKE combing to a despread signal, and a determining device 306 provides temporary determination to the signal subjected to RAKE combing. A re-spreader 308 spreads a replica signal subjected to temporary determination. A divider 309 divides replica signals on a path-by-path basis to correspond to the directivity selected by the selector 301. Adders 310-1 and 310-2 add the replica signals divided by the divider 309 on the directivity-by-directivity. This makes it possible to cancel interference in combination with an array antenna and to reduce the number of calculations and the circuit scale as an entirety of the apparatus.
摘要:
In order to improve system throughput in a radio transmitting apparatus of a multicarrier system in which transmission is performed simultaneously to a plurality of receiving stations using subcarriers, subcarriers are divided into blocks, a receiving station is selected on a block unit basis, and the number of subcarriers per block is varied adaptively for each receiving station based on the propagation environment of that receiving station.
摘要:
A server (191) transmits image information consisting of basic data and complementary data to a router (100) through the Internet (192). The router (100) allocates the basic data to a BS (110) of a cellular system (193) and the complementary data to an AP (120) of a wireless LAN system (194). The BS (110) transmits the basic data to a MS (150) and the AP (120) transmits the complementary data to the MS (150). When the MS (150) is located in the area of the cellular system (193), the MS always maintains a communication channel with the BS (110) and when the MS enters the area of the wireless LAN system (194), the MS also opens a channel with the AP (120) while maintaining the channel with the BS (110) . This allows the user to continue seamless communication.
摘要:
By assigning a plurality of subcarriers 31 to a data channel 33 and assigning fewer subcarriers 32 than the plurality of subcarriers 31 to a control channel 34, and in addition locating the control channel 34 at the center frequency fc of a frequency band used to transmit the data channel 33, on the radio receiving apparatus side, the frequencies of a local signal by which the received signal is multiplied share the same value, thereby speeding up the switching between the control channel and the data channel.
摘要:
Receiving a packet interleaved with an interleave pattern corresponding to the number of times of retransmission, reception apparatus (200) de-interleaves a pilot sequence contained in the packet with de-interleavers (205-1 ∼ 205-N). Correlators (206-1 ∼ 206-N) performs correlation calculation between the de-interleaved pilot sequence and a pilot pattern held in the reception apparatus. Maximum value detection section (207) detects the maximum correlation value among the correlation values to detect the number of times of retransmission. Decision section (209) controls combination circuit (213) and error detection section (217) based on the number of times of retransmission stored in storage section (208) and on the number of times of retransmission detected at maximum value detection section (207). This allows a decrease in throughput to be prevented from occurring even in a case where a reception side receives a packet which is different from one which is requested by the reception side.
摘要:
A subcarrier transmission ON/OFF control system based on an MC-CDMA system capable of improving information transmission efficiency and reception performance while keeping the number of transmission bits constant. Furthermore, a subcarrier transmit power control system based on an MC-CDMA system or OFDM system capable of improving information transmission efficiency and reception performance. The former system based on the MC-CDMA system does not carry out transmission through subcarriers of low reception quality, with no transmit power assigned (transmission OFF), assigns the corresponding transmit power to subcarriers with transmit power assigned (transmission ON) and carries out transmission (subcarrier transmission ON/OFF control). The latter system based on the MC-CDMA system or OFDM system carries out transmission according to a reception level of each subcarrier on the receiving side, with greater transmit power assigned to subcarriers with higher reception levels and smaller transmit power assigned to subcarriers with lower reception levels (subcarrier reverse transmit power control).
摘要:
A base station transmits downlink signals to mobile terminals of users A to C with respective transmission power corresponding to downlink quality. A downlink quality estimating section (106) uses the transmission power from a transmission power control section to compare transmission power between the users, and estimates that a terminal with low transmission power has high downlink quality. The priorities are determined so that the priority is increased as the transmission power is lower. Thus determined priority information is output to a scheduling section (107). The scheduling section (107) performs scheduling based on the priority information. The section (107) assigns DSCH to terminals in ascending order of transmission power. User A is first assigned DSCH, user B is second assigned DSCH, and user C is third assigned DSCH. It is thus possible to perform scheduling and MCS selection of DSCH with the need of information from a terminal eliminated.