摘要:
It is possible to provide a novel pilot transmission method which can calculate an accurate channel estimation value, a MIMO transmission device using the pilot transmission method, and a MIMO reception device which performs communication with the MIMO transmission device. The MIMO transmission device (100) includes a cyclic shift processing unit (150) which cyclically shifts a first pilot signal sequence spread by a spread code 1 and second pilot signal sequence spread by a spread code 2 with different shift amounts. The first pilot signal sequence and the second pilot signal sequence which have been cyclically shifted are transmitted from different transmitting antennas at the same pilot transmission symbol section. Thus, by changing the shift amount of the cyclic shift process executed on each pilot signal sequence spread by the respective spread codes, it is possible to improve the pilot separation accuracy at a reception side. This enables more accurate calculation of a channel estimation value.
摘要:
A wireless communication method of repetition system and the like for ensuring that when the same data symbols are combined, a diversity gain is achieved. In a step (ST 420), a data symbol placing part (105) decides destination places of respective replicated data symbols (S1-S4) such that the same data symbols are not placed at destination place numbers (7,8) of data symbols that exhibit poor channel estimation precisions. In a step (ST 430), the data symbol placing part (105) places, in accordance with the decision in the foregoing step (ST 420), the four data symbols (S1-S4), which are received from a repetition part (102), in one frame received from a channel estimation error predicting part (104).
摘要:
A wireless communication method realizing a large channel capacity even in an environment of high spatial correlation and improving the reception characteristic, a wireless communication system, and a wireless communication device. Signals (X1, X2) are transmitted between antennas (201-1, 201-2) of a base station (200) and antennas (222-1, 222-2) of a mobile station by a space division multiplexing (SDM) system. On the base station (200) side, if channel information estimated by a channel estimating section (204) is known, a weight calculating section (205) calculates a weight, the transmission signal is multiplied by the weight, and diversity transmission from an antenna (201-3) of the base station (200) is carried out. On the mobile station (220) side, the signal transmitted from the base station (200) is received, a signal separating section (203) carries out signal separation of received signals (Y1, Y2), and thereby the transmitted signals (X1, X2) are restored.
摘要:
Provided is a mobile communication system capable of obtaining a diversity effect even when a signal received by a relay station has an error in a corporate relay to which time space encoding is applied. In this mobile communication system, when S1 has no error and S2 has an error, a relay station (1) does not perform relay transmission at time t (Null) and relay-transmits S1* to a base station at time t+T. That is, in this case, the relay station (1) relay-transmits at time t+T only S1 to be transmitted at time t when no error is contained in either S1 or S2. Moreover, when S1 has an error and S2 has no error, the relay station (1) relay-transmits S2 at time t and does not perform relay transmission at time t+T (Null). That is, in this case, the relay station (1) relay-transmits only S2 to be transmitted at time t+T at time t if no error is contained in either S1 or S2.
摘要:
A radio transmitting apparatus, a radio receiving apparatus, a wireless communication method and a wireless communication system wherein even when a channel correlation is large, the channel capacity and the feedback amount can be improved. In ST401, a receiving apparatus (200) determines that the channel correlation value exceeds a predetermined threshold value. In ST402, a transmitting apparatus (100) is instructed to perform 42 MIMO transmission. In ST403, the transmitting apparatus (100) determines a pair of antennas exhibiting the highest channel correlation. In ST406, the receiving apparatus (200) uses, based on the pair information, a channel matrix, which comprises channel estimation values, to calculate a delay shift amount. In ST407, the delay shift amount is fed back to the transmitting apparatus (100). In ST408, the transmitting apparatus (100) uses the pair information and delay shift amount to combine SDM and a cyclic sample delay diversity, thereby transmitting data.
摘要:
A transmitter, a receiver and a communication method enabling improvement of the data rate of an MIMO system. One signal x2 out of the three signals is combined with the other two signals x1, x3 respectively to generate two combined signals x1+x2, x2+x3. The combined signals are transmitted through transmission antennas (102, 103). A signal separating section (106) of the receiver separates the received signals r1, r2 into two signals y1, y2 by a signal separation processing such as the ZF. An MLD processing section (107) generates MLD evaluation formulae using y1, y2 and performs an MLD processing in which x2 is cancelled from y1, y2 and evaluation formulae about x1, x3 are generated, and a maximum likelihood estimation is performed. As a result of the MLD processing, x1, x3 are detected. In a canceling section (108) the detected x1, x3 are canceled from y1, y2, and x2 is detected.
摘要:
A retransmission control scheme and a wireless communication apparatus wherein the efficiency of retransmission control is enhanced to further improve the system throughput. In this wireless communication apparatus (100), an error occurrence factor addressing part (140) receives information related to the error occurrence factor of a transmitted packet or information related to the schemes of forming or transmitting a retransmittal packet corresponding to that error occurrence factor, and switches, based on the received information, the schemes of forming or transmitting the retransmittal packet. In this way, the schemes of forming or transmitting the retransmittal packet can be switched in accordance with the error occurrence factor of the transmitted packet. At the end of receiving the retransmittal packet, therefore, the performing of a decoding processor the like in accordance with that scheme of forming or transmitting can enhance the efficiency of the retransmission control. As a result, the system throughput can be improved.
摘要:
An inventive wireless communication apparatus that, in a wireless communication system to which a secret key scheme is applied, can generate a secret key, which is different from a secret key generated by a third party, even if a wireless signal is intercepted by the third part having an approximate propagation path environment to a receiving wireless communication apparatus. In the inventive apparatus, an eigenvalue selecting part (317) of a secret key generating part (207) selects a maximum one of MIMO channel eigenvalues received from an eigenvalue detecting part (206) and inputs the selected maximum eigenvalue to a quantizing part (327). The quantizing part (327) quantizes the magnitude of the maximum eigenvalue received from the eigenvalue selecting part (317) to produce and input a quantized data to a key generating part (337). The key generating part (337) uses a predetermined scheme to generate a secret key from the quantized data received from the quantizing part (327), and inputs the generated secret key to a control part or the like not shown.
摘要:
There is disclosed a radio communication device capable of preventing wire-tap of an encrypted communication even if a radio signal is wire-tapped by a third person in a radio communication system using the MIMO technique. In this device, an inter-channel correlation calculation unit (104) calculates an inter-channel correlation value between two channels in the MIMO channel according to four channel estimation values inputted from a channel estimation unit (103). The six channel correlation values calculated are all inputted to a channel selection unit (105). The channel selection unit (105) selects a minimum channel correlation value from the six channel correlation values inputted from the inter-channel correlation calculation unit (104) and reports two channels corresponding to the selected channel correlation value to an inter-channel correlation monitoring unit (110) and inputs the channel estimation value of the two channels to a secret key generation unit (106).