JP2007266733A - Random access method, wireless terminal and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for facilitating processing upon occurrence of collision of preambles and avoiding interference with other terminal. <P>SOLUTION: When the number of signatures for specifying a terminal is increased and the signature is separated into a group and a personal in random access and there is no response of AICH (Access Indicator Channel) from a base station to preamble transmission, such a control as increasing the number of repeating transmission of preamble is performed in place of the power ramp control for raising transmission power of preamble. Both preambles of group and personal signatures are processed when the state of line is good, but the signature of group is processed at first and then the signature of personal is processed when the state of line is bad. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile radio communication system, and more particularly to a RACH (Random Access Channel) transmission technique.

  In a random access transmission on a common uplink physical channel, there are 15 access slots every 2 frames separated by 5120 chips, and one or several random access transmissions. These preambles (length 4096 chips) and one message (length 10 ms or 20 ms). Each preamble is configured by repeating a signature of 16 chips in length 256 times, and 16 signatures can be used (see Non-Patent Document 1).

  A physical random access procedure from a UE (User Equipment) that is a wireless terminal is roughly as follows (see Non-Patent Document 2).

1. Select an uplink slot.
2. A signature is randomly selected from a set of signatures available within a given access service class (ASC).

  3. Set the preamble retransmission counter to the maximum value.

  4). Set the preamble power to the initial value.

  5. If the preamble power does not exceed the maximum allowable value, the preamble is transmitted using the selected uplink slot, signature, and preamble transmission power.

6). If no positive or negative acquisition indicator corresponding to the selected signature is detected in the downlink slot corresponding to the selected uplink slot,
6.1 Select the next available access in the set of available RACH subchannels within a given ASC.

    6.2 Randomly select a new signature from the signatures available within ASC.

    6.3 Increase the preamble transmit power by the power ramp step. Here, when the power exceeds the maximum allowable power by 6 dB, the UE transmits the L1 state (no Ack response of AICH (Acquisition Indicator Channel)) to the upper layer.

    6.4 Decrease preamble retransmission counter by one.

    6.5 If the value of the preamble retransmission counter> 0, repeat from step 5; otherwise, convey the status L1 (no AICH Ack response) to the upper layer (MAC) and exit the physical random access procedure.

  7). If a negative acquisition indicator (AI = −1) corresponding to the selected signature is detected in the downlink slot corresponding to the selected uplink slot, the L1 state (AICH Nack received) is set to the upper layer (MAC). Communicate and leave the physical random access procedure.

  8). If a positive acquisition indicator (AI = + 1) corresponding to the selected signature is detected in the downlink slot corresponding to the selected uplink slot, the uplink access of the last transmitted preamble according to the AICH transmission timing parameter After that, a random access message is transmitted in three or four access slots. Note that the transmission power of the control unit for the random access message is made a predetermined amount (Pp-m [dB]) higher than the power of the preamble transmitted last.

  9. The state L1 (“RACH message transmission”) is transmitted to the upper layer, and the physical random access procedure is exited.

  In Patent Document 1, access resources in a random access channel (defined by a slot and a preamble signature, which have a maximum of 15 time slots and 16 preamble signatures in two radio frames, are combined. As a method for efficiently and flexibly accessing and transmitting data (which can use 240 access resources), multiple access resources can be accessed in accordance with different service classes having different access probabilities. A resource group, a means for randomly selecting an access resource from an access resource group corresponding to the currently assigned access service class, a means for transmitting a random access burst using a randomly selected access resource, Up Configuration with a detection means for detecting an event that changes the current access service class into another access service class are disclosed.

  In addition, as transmission control of the preamble, Patent Document 2 discloses that the transmission frequency of the transmission line response calculation preamble is changed according to the time change of the radio propagation environment. A configuration is disclosed in which when the transmission frequency is increased and the fluctuation of the transmission path is small, the transmission frequency of the transmission path response calculation preamble is decreased to improve the data transmission efficiency.

JP 2002-16979 A JP 2002-290295 A ARIB STD-T63-25.211 V3.11.0 Physical channels and mapping of transport channels on Physical channels (FDD), (Release 1999), “5.2 A1 Ph. -13 pages 3GPP TS 25.214 V5.0.0 (2002-03) 3rd Generation Partnership Project; Technological Specification Group and Radio access Network, Physical Layer Proc. (5) 3rd Generation Partnership Project, 3rd Generation Partnership Project. 31 pages

  In the conventional random access procedure described above, even if an access collision occurs in the preamble, it cannot be determined at that time, and the occurrence of the collision is recognized until a CRC (Cyclic Redundancy check) NG (error) is detected through the message. Can not.

  In addition, there is a problem in that interference with other users increases due to power ramping of the preamble during retransmission of the preamble when there is no AICH response.

  Accordingly, it is an object of the present invention to provide a system and method that facilitates processing when a preamble collision occurs and avoids interference with other terminals.

  In order to solve the above-described problems, the invention disclosed in the present application is generally configured as follows.

  The method according to the present invention is a power ramp control for increasing a preamble transmission power when a preamble is retransmitted when an AICH (Access Indicator Channel) from a radio base station (Node-B) is not received for a preamble transmitted by the terminal. Instead, control is performed to increase the number of repetitions of preamble transmission.

  The method according to the present invention provides a personal signature and a group signature that is commonly assigned to a plurality of personal signatures as signatures constituting a preamble, and the group signature by the wireless terminal For transmission of a preamble pattern including a personal signature, if the wireless terminal receives an AICH acknowledgment corresponding to both a group signature and a personal signature from the wireless base station, the wireless terminal transmits a random access message. When the AICH corresponding to the group signature is received from the radio base station, the preamble of the personal signature is transmitted, and the acknowledgment (ACK) of the AICH corresponding to the preamble transmission of the personal signature is transmitted. Receive If, to send a random access message.

  In the method according to the present invention, when the wireless terminal does not receive a corresponding AICH from the wireless base station for transmission of a preamble including a group signature and a personal signature prepared in advance, only the group signature is received. Transmit the preamble of the pattern containing

  In the method according to the present invention, the wireless terminal transmits a preamble pattern including only a group signature, and does not receive an AICH (Acquisition Indicator Channel) corresponding to the preamble of the group signature from the wireless base station. In this case, if it is within the maximum allowable value, the power is increased and the preamble pattern including only the group signature is retransmitted.

The method according to the present invention provides a personal signature and a group signature that is commonly assigned to a plurality of personal signatures as signatures constituting the preamble,
In a random access transmission, the wireless terminal first transmits a preamble pattern including a group signature and a personal signature,
When the wireless terminal does not receive an AICH (Acquisition Indicator Channel) from the wireless base station for transmission of the one preamble pattern, instead of power ramp control that increases the transmission power of the preamble, the wireless terminal Sending another preamble pattern having a larger number of signatures than the one preamble pattern;
For any of the preamble patterns including the group signature and the personal signature prepared, instead of power ramp control for increasing the transmission power of the preamble when retransmitting the preamble when the AICH is not received from the radio base station. , A preamble pattern of only a group signature, which is obtained by further increasing the number of preamble repetitions, is transmitted.

  In the method according to the present invention, the radio terminal transmits a preamble pattern having only a prepared group signature, and the power is a maximum allowable value at the time of retransmission of a preamble when no acquisition indicator is received from the radio base station. If it does not exceed, transmit a preamble pattern of only the group signature with increasing power.

  In the method according to the present invention, the preamble pattern including the group signature and the personal signature includes more group signatures than personal signatures.

  In the method according to the present invention, the wireless terminal supports the preamble of the group signature and the personal signature from the wireless base station for transmission of a preamble pattern including the group signature and the personal signature. When an acquisition indicator acknowledgment (AICH ACK) is received in each slot, a random access message is transmitted.

  In the method according to the present invention, the wireless terminal receives an AICH corresponding to the preamble of the group signature from the wireless base station for transmission of a preamble pattern including the group signature and a personal signature. If so, a preamble pattern including only the personal signature is transmitted.

  In the method according to the present invention, with respect to transmission of a preamble pattern including only the personal signature, an acknowledgment (AICH ACK) of an acquisition indicator is received from the radio base station in each slot corresponding to the personal signature. The wireless terminal transmits a random access message.

  In the method according to the present invention, a correlation value between a group signature and a personal signature is calculated at a radio base station that receives a preamble transmission from the radio terminal, and a correlation value between the group signature and the personal signature is calculated. Are equal to or greater than predetermined first and second threshold values, respectively, AICH patterns corresponding to the preamble patterns of the group signature and the personal signature are returned to the wireless terminal corresponding to the preamble patterns.

  In the method according to the present invention, when the correlation value of the group signature is larger than the first threshold value and the correlation value of the personal signature is smaller than a second threshold value in the radio base station, An AICH (Acquisition Indicator Channel) pattern including an acknowledgment of the acquisition indicator is returned in each slot corresponding to the signature.

  In the method according to the present invention, when the correlation value of the group signature is larger than the third threshold value in the radio base station, the correlation value is obtained at another timing, and the correlation value is larger than the third threshold value. Return the AICH pattern corresponding to the preamble pattern of the group signature only.

  The radio terminal according to the present invention is a power ramp that increases the transmission power of a preamble when a preamble is retransmitted when an AICH (Access Indicator Channel) is not received from a radio base station for a preamble transmitted by the radio terminal during random access transmission. Instead of control, control is performed to increase the number of repetitions of preamble transmission. According to the present invention, a group signature and a personal signature are provided in a signature constituting the preamble, a preamble pattern including the group signature and the personal signature is transmitted, and the preamble including the group signature and the personal signature is transmitted. In response to transmission, when a preamble is retransmitted when an AICH (Access Indicator Channel) from a radio base station is not received, another preamble pattern including a group signature and a personal signature is transmitted, and a prepared group signature and For another preamble pattern including a personal signature, the preamble retransmission when no AICH (Access Indicator Channel) is received from the radio base station. Time, and transmits the preamble pattern of only the group signature.

  In the radio terminal according to the present invention, even when transmitting a preamble pattern that includes the most group signatures among the preamble patterns, at the time of preamble retransmission when no AICH (Access Indicator Channel) is received from the radio base station If the power does not exceed the maximum allowable value, a preamble pattern including the most group signatures is transmitted with increasing power. In the wireless terminal according to the present invention, the pattern includes more group signatures than personal signatures.

  In the wireless terminal according to the present invention, for the preamble transmission including the group signature and the personal signature, the AICH received from the wireless base station has a pattern including an ACK response to the group signature and the personal signature. If so, send a random access message.

  In the wireless terminal according to the present invention, when the AICH received from the wireless base station with respect to the preamble transmission of the pattern including the group signature and the personal signature is a pattern including an ACK response to the group signature, Send a preamble of a pattern that contains only a personal signature.

  In the wireless terminal according to the present invention, when the AICH ACK response is received from the wireless base station in response to the transmission of the preamble having the pattern including only the personal signature, the terminal transmits a random access message.

  According to the present invention, as a radio base station that receives preamble transmission from the radio terminal, a correlation value between the group signature and the personal signature is calculated, and the correlation value between the group signature and the correlation value between the personal signatures are calculated respectively. 1. If the value is equal to or greater than the second threshold, the AICH ACK response pattern corresponding to the group signature and the personal signature is returned to the terminal corresponding to the preamble pattern, and the correlation value of the group signature is the first value A radio base station is provided that identifies a group signature if greater than a threshold.

  In the radio base station according to the present invention, when the correlation value of the group signature is larger than the first threshold value and the correlation value of the personal signature is smaller than the second threshold value, the response pattern of the AICH of the group signature is return.

  In the radio base station according to the present invention, when the correlation value of the group signature is larger than the third threshold, the correlation value is obtained at another timing, and when the correlation value is larger than the third threshold, the group signature AICH ACK response pattern corresponding to only the preamble pattern is returned to the terminal.

  The present invention increases the number of signatures for identifying a terminal in random access, separates the signature into a group and a personal, and at the time of preamble retransmission when there is no AICH response from the radio base station for preamble transmission, Instead of power ramp control for increasing the preamble transmission power, control for increasing the number of preamble transmission repetitions is performed. In the present invention, when the line condition is good, both the group signature and the personal signature are processed. When the line condition is not good, the group signature is processed first, and then the personal signature is processed. I do.

  According to the present invention, by separating a signature for identifying a terminal into a group and a personal, it becomes easy to identify a group even when a preamble collision occurs.

  In addition, according to the present invention, when the preamble is retransmitted when there is no AICH response, interference or the like can be suppressed by increasing the number of repetitions of preamble transmission instead of power ramp control for increasing the preamble transmission power. it can.

  In order to describe the present invention described above in more detail, it will be described below with reference to the accompanying drawings. The present invention separates a signature (Signature) that constitutes a preamble transmitted from a terminal in random access transmission into a group (Group) and a personal (Personal), and transmits preamble transmission instead of power ramping control of the preamble. Control to increase the number of repetitions. For example, one group signature is assigned to a group of 16 personal signatures.

  When transmitting a random access transmission preamble, a radio terminal (UE) first transmits a preamble pattern including a group signature and a personal signature (see Preamble 1 in FIG. 1A). In the case of not receiving an acquisition indicator (Acquisition Indicator) from the radio base station (Node-B) to the corresponding downlink slot for transmission of the preamble pattern, instead of power ramping control, group signature and personal Another preamble pattern (see Preamble 2 in FIG. 1B) is transmitted by increasing the number of signature repetitions than the preamble pattern. .

  When AICH is not received from the radio base station for transmission of all preamble patterns (see Preambles 1 and 2 in FIGS. 1A and 1B) including the prepared group signature and personal signature, The radio terminal (UE) transmits a preamble pattern of only the group signature (Preamble 3 in FIG. 1C) instead of the power ramp control for increasing the transmission power of the preamble, by further increasing the number of repetitions of the group signature. To do.

  Even when a radio terminal (UE) transmits a preamble pattern including only a group signature (Preamble 3 in (c) of FIG. 1), power is transmitted when the preamble is retransmitted when the AICH is not received from the radio base station. If the maximum allowable value is not exceeded, power ramp control is performed, and retransmission is performed by increasing the transmission power of the preamble pattern (Preamble 3 in FIG. 1C) including only the group signature. Alternatively, the frequency may be changed and retransmitted.

  In the present invention, in the preamble pattern, the group signature (G) is included more than the personal signature (P) (in the preambles 1 and 2 in FIGS. 1A and 1B, the group signature is a personal signature). Twice the signature).

  In the present invention, for transmission of a preamble pattern (see Preambles 1 and 2 in FIGS. 1A and 1B) including a group signature and a personal signature, the radio base station transmits the group signature and When a positive acknowledgment (ACK) of an acquisition indicator (Acquisition Indicator) is received for transmission of a preamble pattern of a personal signature (see (ICH) and (I) of AICH1 and AICH2), a random access message Send.

  For the transmission of a preamble pattern including both a group signature and a personal signature (see preambles 1 and 2 in FIGS. 1A and 1B), only the AICH corresponding to the group from the radio base station is transmitted. When received (see AICH1a and AICH2a in FIGS. 1H and 1J), a preamble pattern including only the personal signature (P) (see Preambles 4 and 5 in FIGS. 1D and 1E) Send. In this case, the same number of personal signatures as the number of group signatures of the preamble pattern (see Preambles 1 and 2 in FIGS. 1A and 1B) including the group signature and personal signature transmitted earlier are included. The included preamble pattern (Preambles 4 and 5 in FIGS. 1D and 1E) may be transmitted.

  A preamble pattern including only the personal signature transmitted in response to the reception of the AICH for the preamble of the group signature (see AICH 1a, AICH 2a, and AICH 3 in FIGS. 1 (h) and (j)). d), (e), (F) Preamble 4, 5, 6), the AICH ACK response from the radio base station (FIG. 1, (dl), (m), (n) AICH 4, 5, If 6) is received, the terminal transmits a random access message.

  As described above, in the present invention, when the preamble is retransmitted when there is no AICH response from the radio base station for the transmission of the preamble (Preamble 1), instead of the power ramp control for increasing the transmission power of the preamble (Preamble 1). Then, a preamble (Preamble 2 or Preamble 3) is transmitted. When the line condition is good, both the group signature and personal signature are processed. When the line condition is not good, the group signature is processed, and when the AICH for the group signature is received, the personal signature is processed. Process the signature.

  According to the present invention, interference with the terminal is avoided, and even when a preamble collision occurs, it is easy to identify a group. In the following, description will be made in accordance with examples.

  Referring to FIG. 1, a preamble and an AICH procedure in one embodiment of the present invention are shown. In FIG. 1, the part marked with G in the square □ is the transmission data of the group signature, and is repeatedly transmitted by the number of □. The portion marked with P in the square □ is personal signature transmission data, and is repeatedly transmitted by the number of □. In the preambles 1 and 2 (FIGS. 1A and 1B), the group signature part has a transmission amount twice as large as that of the personal signature part. This is to improve the detection characteristics.

  In this embodiment, 16 signature numbers are prepared for each of the group signature and the personal signature as in the 3GPP (3rd Generation Partnership) specification. Group signatures and personal signatures do not use the same signature (different from each other). Therefore, 16 × 15 = 240 combinations as a whole. Although not particularly limited, as shown in FIG. 1, in the example where the signature is i = 0 to 15, for example, assuming a preamble of 4096 chips length, the preamble is a pattern in which a signature of 16 chips length is repeated 256 times. Consists of.

  Preamble patterns Preamble 1 and 2 in FIGS. 1A and 1B include group (G) and personal (P) signature data, and preamble pattern Preamble 3 in FIG. 1C is a group signature. Only the (G) is repeated, and the preamble patterns Preambles 4, 5, and 6 in FIGS. 1D, 1E, and 1F are repeated only for the personal signature (P).

  In addition, AICH1 and AICH2 in FIGS. 1G and 1I correspond to both a group signature and a personal signature with respect to the preamble patterns in FIGS. 1A and 1B, respectively. This corresponds to the case where AICH is received.

  1 (h) and (j) AICH1a and AICH2a correspond to the patterns when the AICH corresponding to only the group signature is received with respect to the preamble patterns of (a) and (b) of FIG. is doing.

  The AICH 3 in FIG. 1 (k) corresponds to the AICH pattern for the pattern of only the group signature (G) in FIG. 1 (c).

  1 (l), (m), and (n) AICH4, 5, and 6 correspond to the AICH of the preamble of the pattern of only the personal signature of (d), (e), and (f) of FIG. 1, respectively. is doing.

  FIG. 2 is a flowchart for explaining the operation of the terminal according to the embodiment of the present invention. FIG. 2 shows a procedure on the radio terminal side in random access transmission in a common uplink physical channel between the radio terminal (UE) and the radio base station (Node-B).

  The wireless terminal (UE) transmits preamble 1 (see Preamble 1 in FIG. 1A) at timing 1 (step 101). Preamble 1 consists of two groups and one personal signature repetition.

  If the wireless terminal receives an AICH from the wireless base station in response to the transmission of preamble 1 (Yes in step 102), is the AICH corresponding to only the group signature (see AICH 1a in (h) of FIG. 1)? It is determined whether or not (step 104). As a result of the determination in step 104, in the case of the AICH corresponding to the personal signature in addition to the group signature (see AICH1 in FIG. 1G), the wireless terminal transmits a random access message (step 105).

  As a result of the determination in step 104, in the case of an AICH with only a group signature (see AICH 1a in FIG. 1 (h)), the wireless terminal uses the pattern of preamble 4 (see Preamble 4 in FIG. 1 (d)) at timing 2. Transmit (step 106). That is, the wireless terminal transmits a preamble having only a personal signature.

  When the AICH is not received for transmission of the preamble 4 of the personal signature pattern (No in Step 107), the process temporarily stops (Step 108).

  On the other hand, when the wireless terminal receives the AICH (see (l) in FIG. 1) corresponding to the preamble 4 of the pattern having only the personal signature (Yes branch in step 107), the wireless terminal receives both the group and personal signatures. On the other hand, since the ACK response of AICH has been received, the wireless terminal transmits a random access message (step 109).

  If the AICH is not received in step 102, the wireless terminal transmits preamble 2 (Preamble 2 in FIG. 1B) at timing 1 (step 103). As for the unit of the preamble 2 pattern, the number of repetitions of the group signature and the personal signature is increased to twice that of Preamble 1 in FIG.

  When the AICH is received from the radio base station in response to the transmission of preamble 2 (Yes in step 110), it is determined whether or not the AICH corresponding to the group signature (see AICH 2a in (j) of FIG. 1) is received. (Step 112). When the AICH corresponding to the preamble of the personal signature is also received (in the case of AICH2 in (i) of FIG. 1), a RACH (random access) message is transmitted (step 113).

  As a result of the determination in step 112, when only the group signature is present (when it is the AICH 2a of (j) in FIG. 1), the wireless terminal transmits the preamble 5 of only the personal signature (Preamble 5 of FIG. 1 (e)) at timing 2. (Refer to step 114). In the preamble 5, the personal signature (P) is continuous for 4 slots corresponding to the pattern of the group signature (G) of the preamble 2.

  When the AICH is not received for the preamble 5 of the personal signature (NO branch of step 115), it is temporarily stopped (step 116). On the other hand, when AICH (see AICH5 in FIG. 1 (m)) is received (Yes branch of step 115), RACH message is transmitted (step 117).

  If the AICH is not received from the radio base station in Step 110 for the transmission of the preamble 2 at the timing 1, the radio terminal transmits the pattern of the preamble 3 at the timing 1 (see Preamble 3 in FIG. 1C) ( Step 111). The preamble 3 is all group signature data.

  When the AICH is received in response to the transmission of the preamble 3 (Yes branch in Step 118), the wireless terminal transmits the preamble 6 (see Preamble 6 in FIG. 1 (f)) at the timing 2 (Step 120). The preamble 6 pattern is all personal signatures.

  When the AICH (see (n) in FIG. 1) is received for the transmission of the preamble 6 (Yes branch of Step 123), the wireless terminal transmits a random access message (Step 124) and does not receive the AICH ( No branch of step 123), and temporarily stops (step 125).

  If the AICH is not received in step 118, the wireless terminal increases the power if the preamble power is less than the maximum allowable value (maximum value) (NO branch of step 119). The power ramp control is performed for the first time, and preamble 3 is transmitted at timing 3 (step 121). If the preamble power is greater than or equal to the maximum allowable value, the power is temporarily stopped (step 122).

  Thus, according to the present embodiment, the wireless terminal transmits with the preamble 1 pattern (FIG. 1A). ACK / NACK for the preamble 1 pattern is the AICH1 pattern (FIG. 1 (g)), but the propagation environment is not sufficiently good and the reception level of the radio base station (Node-B) is not sufficiently high. Cannot take a personal signature, but can take a group signature, so it becomes the AICH1a pattern (FIG. 1 (h). That is, the AICH1a pattern is an ACK (acknowledgment) of the access indicator for the group signature. , NACK (negative acknowledgment).

  The patterns of preambles 4, 5, and 6 (FIGS. 1D, 1E, and 1F) are wireless terminals for personal signatures when an ACK is returned in the AICH1a, AICH2a, and AICH3 patterns, respectively. Sent from

  In this embodiment, first, preamble 1 (FIG. 1A) is transmitted, and when AICH is not received, preamble 2 (FIG. 1B) is transmitted, and when AICH is not received, preamble 3 (FIG. 1) is transmitted. (C)) is transmitted. Preambles 1, 2, and 3 (FIGS. 1A, 1B, and 1C) are transmitted at the same timing (Timing 1), but preambles 4, 5, and 6 (FIGS. 1D and 1E) , (F)) are transmitted at different timings 2.

  In this embodiment, when transmitting only the personal signature, the timing is divided so as not to interfere with the transmission of the group signature so that the radio base station can distinguish.

  When the output power exceeds the allowable maximum value and the number of repetitions of preamble transmission cannot be increased any more, the preamble 3 pattern is transmitted with higher power at a different timing 3.

  FIG. 3 is a flowchart for explaining the operation on the radio base station side. When the correlation value C1 (k, s1) of the group signature is greater than or equal to a predetermined threshold value 1, it is determined that the group signature has been detected. When both a group signature and a personal signature are detected in the pattern of preamble 1 (FIG. 1A) and preamble 2 (FIG. 1B) (determination of s1 = s2 in step 209 in FIG. 3) Yes) is considered that only the group signature has been identified. This is because the group signature and personal signature are never the same.

  Referring to FIG. 3, at timing 1 (corresponding to Timing 1 in FIG. 2), correlation value C1 (k, s1) (k = 0, 1, 2) (s1 = 0, 1-15), correlation value C2 ( k, s2) (k = 0, 1, 2) (s2 = 0, 1-15) are respectively calculated (step 201). The correlation value C1 (k, s) and the correlation value C2 (k, s) are given by the following equations (1) and (2), respectively.

  C1 (k, s) (k = 0, 1, 2) is the correlation value for the group signature part of Preambles 1, 2, 3 (see FIGS. 1 (a), (b), (c)), C2 (k , S) (k = 0, 1) is a correlation value for the personal signature part. corr (i, s) is a cross-correlation between the received signal sequence i and the signature pattern s. In the expressions (1) and (2), the braces {} correspond to the calculations of i = 0 to 7 in FIG. As shown in FIG. 1, in the example where the signature is 0 to 15, one corr (i, s) is calculated with 16 chips. N is the number of received signal sequences, and assuming a preamble of 4096 chips, N is 4096/16 = 256.

  Next, 16 absolute values of correlation values C1 (k, s1) calculated in step S201 are extracted in descending order (step 202).

  If the absolute value | C1 (k, s1) | of the correlation value C1 is larger than the threshold value 1 (Yes branch of step 203) and k is different from 2 (Yes branch of step 205), the personal signature part When the absolute value | C2 (k, s2) | of the correlation value of is greater than a predetermined threshold value 2 (Yes branch of step 207), and when s1 ≠ s2 (No branch of step 209), the group When it is determined that both the signature and the personal signature are used, and A = 0 for both the group and the personal, AICH1 (see FIG. 1 (g)) is transmitted when k = 0, and AICH2 (FIG. 1) when k = 1. (See (i)). When s1 = s2 (Yes branch at step 209), the group signature and the personal signature are the same, and the process proceeds to step 203.

  When the absolute value | C1 (k, s1) | of the correlation value C1 is smaller than the threshold value 1 in step 203 (No branch in step 203), the process temporarily stops (step 204).

  In step 205, if k = 2, it is specified that only the group signature is present, AICH3 (see FIG. 1 (k)) is transmitted (step S206), and the process proceeds to step S211.

  If it is determined in step 205 that k = 2 is not satisfied, the process proceeds to step 207. When the absolute value | C2 (k, s2) | of the correlation value C2 is equal to or smaller than the threshold value 2 (No branch in Step 207) in the determination of Step 207, it is specified that only the group signature is present. AICH 1a (see FIG. 1 (h)) is transmitted to the downlink slot corresponding to the uplink slot of FIG. 1 (a), and when k = 1, the preamble 2 (see FIG. 1 (b)) is transmitted. The AICH 2a (see FIG. 1 (j)) is transmitted to the corresponding downlink slot, and the process proceeds to step S211.

  In step 211, the current k is saved in k2, and the state flag flag [k] = 1 prepared corresponding to k is set (only the group signature is specified for the preamble k, and the AICH is transmitted. Record that). The flag array (register) is prepared in a computer in the radio base station.

  At timing 2 (corresponding to timing 2 in FIG. 2), the correlation value C1 (k, s) of the group signature is calculated (step 212). When the absolute value | C1 (k, s) | of the correlation value C1 is larger than the threshold value 3 (Yes branch in step 213), the personal signature is specified. When k = 0, AICH4 (see FIG. 1 (l)) is transmitted as the AICH for the personal signature of the pattern of FIG. 1 (d), and when k = 1, the personal ID of the pattern of FIG. 1 (e) is transmitted. AICH5 (see FIG. 1 (m)) for the signature is transmitted. When k = 2, AICH6 (see FIG. 1 (n)) for the personal signature having the pattern of FIG. 1 (f) is transmitted. When the absolute value | C1 (k, s) | of the correlation value C1 is equal to or smaller than the threshold value 3 in step 213, the process temporarily stops (step 214).

  According to this embodiment, the number of signatures increases, so that collision of preamble access is less likely to occur. Further, since the control is performed by increasing the number of repetitions instead of the power ramping of the preamble, it is possible to suppress interference with other users.

  As another embodiment of the present invention, the frequency may be changed at the time of transmitting the preambles 4, 5, 6 instead of changing the timing. When transmitting with the power level of the preamble 6 increased, the frequency may be changed instead of the timing. Alternatively, the timing may be changed for each of the preambles 1, 2, 3, 4, 5, and 6.

  The present invention naturally includes terminals and radio base stations whose operations have been described with reference to FIGS. 2 and 3 within the scope of the present invention.

  Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the configurations of the above-described embodiments, and various modifications that can be made by those skilled in the art within the scope of the present invention. Of course, including modifications.

It is a figure explaining the example of operation | movement of UE of one Example of this invention, and the pattern of AICH corresponding to the pattern of a preamble is shown. 3 is a flowchart illustrating an operation of a UE in an embodiment of the present invention. It is a flowchart which shows the operation | movement by the side of the wireless base station in one Example of this invention.

Explanation of symbols

G group signature transmission data P personal signature transmission data 101-125, 201-215 steps

Claims (32)

  In the case of random access transmission, if an acquisition indicator (Acquisition Indicator) is not received for the preamble transmitted by the wireless terminal, control is performed to increase the number of repetitions of preamble transmission instead of power ramp control to increase the preamble transmission power. A random access method characterized by that. As a signature constituting the preamble, a personal signature and a group signature that is commonly assigned to a plurality of personal signatures are provided.
An AICH (Acquisition Indicator Channel) corresponding to both the group signature and the personal signature is transmitted from the wireless base station to the transmission of a preamble including a group signature and a personal signature by the wireless terminal. If the wireless terminal receives an acknowledgment (ACK), it sends a random access message,
When receiving an AICH corresponding to only the group signature from the radio base station, the radio terminal transmits a preamble including only a personal signature,
The wireless terminal transmits a random access message when an AICH acknowledgment corresponding to transmission of a preamble including only the personal signature is received from the wireless base station. The random access method described.   The wireless terminal transmits a preamble including only a group signature when it does not receive an AICH in response to transmission of a preamble including a group signature and a personal signature prepared in advance. 2. The random access method according to 2.   When the wireless terminal transmits a preamble including only the group signature and does not receive an AICH corresponding to the preamble of the group signature from the wireless base station, the wireless terminal increases power if it is within a maximum allowable value. 4. The random access method according to claim 3, wherein a preamble pattern including only the group signature is retransmitted. As a signature constituting the preamble, a personal signature and a group signature that is commonly assigned to a plurality of personal signatures are provided,
In a random access transmission, the wireless terminal first transmits a preamble pattern including a group signature and a personal signature,
If the wireless terminal does not receive an acquisition indicator channel (AICH) from the wireless base station for transmission of the one preamble pattern, instead of power ramp control for increasing the transmission power of the preamble, the wireless terminal Sending another preamble pattern having a greater number of personal signatures than the one preamble pattern;
For any of the preamble patterns including the group signature and the personal signature prepared, instead of power ramp control for increasing the transmission power of the preamble when retransmitting the preamble when the AICH is not received from the radio base station. A random access method characterized by transmitting a preamble pattern of only group signatures, further increasing the number of group signatures.   If the wireless terminal does not exceed the maximum allowable value at the time of retransmission of a preamble when the corresponding AICH is not received from the wireless base station for transmission of a preamble pattern having only a prepared group signature, 6. The random access method according to claim 5, wherein a preamble pattern of only a signature is transmitted with increased power.   6. The random access method according to claim 2, wherein the preamble pattern including the group signature and the personal signature includes more group signatures than personal signatures.   The wireless terminal sends an AICH acknowledgment (ACK) corresponding to the group signature and the personal signature from the wireless base station in response to transmission of a preamble pattern including the group signature and the personal signature. 6. The random access method according to claim 5, wherein a random access message is transmitted when received.   When the wireless terminal receives an AICH of the group signature from the wireless base station in response to transmission of a preamble pattern including the group signature and a personal signature, a preamble including only the personal signature is received. 6. The random access method according to claim 5, wherein the pattern is transmitted.   When receiving an AICH acknowledgment (ACK) from the radio base station for transmission of a preamble pattern including only the personal signature, the radio terminal transmits a random access message. The random access method according to claim 9.   In the radio base station that receives the preamble transmission from the radio terminal, the correlation values of the group signature and the personal signature are calculated, and the correlation value of the group signature and the correlation value of the personal signature are respectively determined in advance. 6. The random access method according to claim 5, wherein if the value is equal to or greater than the second threshold value, an AICH corresponding to a group signature and a personal signature is returned to the wireless terminal corresponding to the preamble pattern.   In the radio base station, when the correlation value of the group signature is larger than the first threshold and the correlation value of the personal signature is smaller than a second threshold, the AICH corresponding to the group signature is The random access method according to claim 11, wherein the random access method is returned to the wireless terminal.   In the radio base station, when the correlation value of the group signature is larger than the third threshold, the correlation value is obtained at another timing, and when the correlation value is larger than the third threshold, the preamble of only the group signature 12. The random access method according to claim 11, wherein an AICH corresponding to a pattern is returned to the wireless terminal.   The wireless terminal transmits a preamble pattern including only the personal signature at a timing different from the transmission timing of the preamble pattern including the group signature and the personal signature or by changing the frequency. 10. The random access method according to claim 2 or 9, characterized in that:   When the wireless terminal transmits a preamble pattern including only the group signature and does not receive an AICH corresponding to the preamble of the group signature from the wireless base station, the frequency is changed and only the group signature is transmitted. The random access method according to claim 3, wherein a preamble pattern including: is retransmitted.   During random access transmission, the number of repetitions of preamble transmission instead of power ramp control for increasing the preamble transmission power when retransmitting the preamble when the AICH (Acquisition Indicator Channel) from the radio base station is not received for the transmitted preamble A wireless terminal characterized by performing control to increase the number of terminals. As a signature constituting the preamble, a personal signature and a group signature assigned in common to a plurality of personal signatures are provided.
For transmission of a preamble pattern including a group signature and a personal signature, if an AICH acknowledgment (ACK) corresponding to the preambles of both the group signature and the personal signature is received from the radio base station, random Send an access message,
If an AICH acknowledgment corresponding to the preamble of the group signature is received from the radio base station, a preamble pattern including only the personal signature is transmitted,
The wireless terminal transmits a random access message when an AICH acknowledgment corresponding to transmission of a preamble pattern including only the personal signature is received from the wireless base station. Item 17. A wireless terminal according to Item 16.   In response to transmission of a preamble pattern including a group signature and a personal signature prepared in advance, when a corresponding AICH is not received from the radio base station, a preamble pattern including only a group signature is transmitted. The wireless terminal according to claim 17.   When transmitting a preamble pattern including only a group signature and not receiving an AICH corresponding to the preamble of the group signature from the radio base station, if it is within the maximum allowable value, increase the power, The wireless terminal according to claim 17, wherein the preamble pattern including only the signature is retransmitted. As a signature constituting the preamble, a personal signature and a group signature assigned in common to a plurality of personal signatures are provided.
In the case of random access transmission, first, a preamble pattern including a group signature and a personal signature is transmitted,
When the AICH (Acquisition Indicator Channel) is not received from the radio base station for the transmission of the one preamble pattern, the number of group signatures and personal signatures is set instead of the power ramp control for increasing the transmission power of the preamble. , Send another preamble pattern that is larger than the one preamble pattern,
For any of the preamble patterns including the group signature and the personal signature prepared, instead of power ramp control for increasing the transmission power of the preamble when retransmitting the preamble when the AICH is not received from the radio base station A wireless terminal, wherein the number of group signatures is further increased, and a preamble pattern of only group signatures is transmitted and controlled.   If the power does not exceed the maximum allowable value when the preamble is retransmitted when the AICH is not received from the radio base station in response to the transmission of the prepared group signature only preamble pattern, the group signature only preamble pattern 21. The wireless terminal according to claim 20, wherein the power is transmitted at a higher power.   21. The wireless terminal according to claim 17, wherein the preamble pattern including the group signature and the personal signature includes more group signatures than personal signatures.   In response to transmission of a preamble pattern including the group signature and personal signature, an AICH acknowledgment (ACK) corresponding to the preamble of the group signature and personal signature is received from the radio base station. The wireless terminal according to claim 20, wherein a random access message is transmitted.   In response to the transmission of the preamble pattern including the group signature and the personal signature, when the AICH acknowledgment (ACK) corresponding to the group signature is received from the radio base station, only the personal signature is received. 21. The wireless terminal according to claim 20, wherein a preamble pattern including the transmitted preamble pattern is transmitted.   The wireless terminal transmits a random access message when an AICH acknowledgment (ACK) is received from the wireless base station for transmitting a preamble having a pattern including only the personal signature. The wireless terminal according to claim 24.   The preamble pattern including only the personal signature is transmitted at a timing different from the transmission timing of the preamble pattern including the group signature and the personal signature or by changing the frequency. The wireless terminal according to claim 17 or 24.   When transmitting a preamble pattern including only the group signature and not receiving an AICH corresponding to the preamble of the group signature from the radio base station, changing the frequency, the preamble pattern including only the group signature The wireless terminal according to claim 20, wherein the wireless terminal is retransmitted. In the radio base station that receives preamble transmission from the radio terminal according to any one of claims 20 to 27,
When the correlation value of each of the group signature and the personal signature is calculated, and the correlation value of the group signature and the correlation value of the personal signature are equal to or greater than the first and second threshold values, respectively, the preamble pattern Correspondingly, an AICH corresponding to a group signature and a personal signature is returned to the wireless terminal.   Returning an AICH corresponding to a group signature to the wireless terminal if the correlation value of the group signature is greater than the first threshold and the correlation value of the personal signature is less than a second threshold; The radio base station according to claim 28.   When the correlation value of the group signature is larger than the third threshold, the correlation value is obtained at another timing, and when the correlation value is larger than the third threshold, the AICH corresponding to the preamble pattern of only the group signature 29. The radio base station according to claim 28, wherein: is returned to the radio terminal.   A wireless communication system comprising the wireless terminal according to any one of claims 16 to 27. A radio communication system comprising the radio base station according to any one of claims 28 to 30.

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