KR100327104B1 - Arbitrary connection apparatus and method of reverse common channel in code division multiple access method - Google Patents

Abstract

The present invention relates to a random access apparatus and method for transmitting data through a common channel by a plurality of terminals in a code division multiple access scheme. According to the present invention, a preamble signature according to a feature of data is provided. ), UEs transmit a preamble using one preamble signature randomly selected from among preamble signatures corresponding to the data to be transmitted, and the base station performs initial synchronization for all possible preambles, and then All UEs are notified of the acquisition, and the UEs that transmit the preamble check whether the preamble signature sent by the UE is captured, and then transmit data to be transmitted or retransmit the preamble using the newly selected preamble signature. line And to reduce the interference, improve the network efficiency, by performing a fast retransmission by the retransmission of the preamble unit is able to quickly access the appropriate power level can be increased two hours natural properties.

Description

Random Access Device and Method for Reverse Common Channel in Code Division Multiple Access

The present invention relates to a random access apparatus and method for transmitting data through a common channel by a plurality of terminals in a code division multiple access scheme. More particularly, the present invention relates to any one of an assigned preamble signature. Select and transmit the preamble, and the base station broadcasts whether the preamble is acquired by performing the initial synchronization to all terminals, the terminal confirms whether the preamble sent by the terminal after transmitting the data to be transmitted or retransmitted accordingly accordingly, unnecessary Random access of reverse common channel in code division multiple access method that improves network delay by reducing interference and reducing interference signal, improving network efficiency, and fast retransmission by preamble alone, so that proper power level can be quickly accessed. Device and To provide the law.

The mobile communication service, which is rapidly growing in demand, is mainly a type of service that enables voice information to be transmitted while on the move. The mobile communication service supporting data service has not been activated yet, but the signal of the video during the movement is simple in data such as e-mail. The demand for reception is on the rise. In particular, research on IMT-2000 (International Mobile Telecommunication-2000) for 3G mobile telecommunications services, which supports not only voice signals but also simple data to video, can be serviced anywhere in the world through internationally integrated standards. Actively done in In addition, although there are some limitations in mobility, researches for high-speed data transmission are being conducted. Especially, the wireless LAN proposed in the IEEE 802.11 standard has already commercialized a product capable of data transmission of 2 Mbps (Mega bit per sec). It is becoming.

In general, for high speed data transmission as described above, the circuit-switch currently used in public switched networks, digital cellular and personal portable communication systems is not preferable because of inefficient use of finite channels. Therefore, in order to solve the shortcomings of the circuit-switched scheme, IMT-2000, which is currently being studied as a local area network or a standard of the next generation mobile communication system, applies a packet-switch for high-speed data transmission. Doing.

In addition, the spread spectrum method, which is a signal method of code division multiple access (CDMA) applied in the digital cellular system that is currently being serviced, has an increased capacity and cannot be eavesdropped from the outside. The advantages of being able to communicate reliably in the multipath environments that arise are demonstrated.

In the IMT-2000 system, which is currently active in standardization, the basic requirement is to support packet data as well as existing voice data.However, due to the nature of packet data, the method of using a dedicated channel like the existing voice can efficiently use resources. There is a disadvantage that can not be used. In other words, data that is generated continuously such as voice data is allocated and used as a dedicated channel, but in case of discontinuous and variable packet data, if a dedicated channel such as voice data is used, the system supports it. There is a problem that does not satisfy the capacity.

Therefore, by using an appropriate number of reverse channels in common, it is possible to accommodate various services within the capacity range with efficient use of resources. Moreover, the efficient use of resources using the reverse common channel will be essential because it is expected that the number of data to be transmitted will increase as subscribers increase in the future.

Currently, the ALOHA method is known as the most effective method for channel access and data transmission using the reverse common channel. The ALOHA scheme is a representative random access scheme developed at the University of Hawaii in 1970 as a protocol for wireless networks between islands in Hawaii. In addition, in the ALOHA method, data transmission efficiency is also lowered by transmitting without a separate time schedule between the base station and the terminal, and when there are many terminals, network collision occurs frequently due to frequent collisions between transmission data. The slot ALOHA was set to set the standard time between the base station and the terminal. That is, even if data to be transmitted from the terminal is allowed to be transmitted only at the reference time, the ratio of pure data in one data transmission increases, thereby increasing the data transmission efficiency, and in addition to the data transmission from the other terminal. There is an advantage that the overall efficiency of the network is improved by reducing the probability of being interrupted.

Hereinafter, a conventional ALOHA protocol using a code division multiple access scheme will be described with reference to FIG. 1.

1 illustrates a process for data transmission in the ALOHA protocol using a conventional code division multiple access scheme.

According to FIG. 1, a terminal transmits data through one access attempt, and the access attempt is composed of a plurality of access sub-attempts, and the access bush diagram is a plurality of access attempts. An access probe sequence consists of a plurality of access probes.

The access probe evaluates the channel condition before transmitting the actual data and transmits only the pilot channel without any information for initial synchronization and code synchronization tracking of the code and the base station code used by the terminal, followed by the preamble and the access information. Or an access channel message capsule containing user data.

A terminal that wants to transmit an access signal or data through a connection common process configured as described above preferentially transmits one access probe at a predetermined power level. In this case, the power level uses a minimum power to reduce the influence of interference on other terminals transmitting data through a dedicated channel or transmitting data through another reverse common channel.

The terminal attempting to transmit data to the first access probe receives whether the data transmitted from the base station succeeds for a predetermined time TA. However, if the data transmission of the first access probe fails, it waits for a certain time (RT) and attempts to retransmit to a power level that is increased by a certain level (PI) above the power level of the first access probe.

Through the above process, data transmission is continuously attempted through the access probe. However, if the data transmission is not successful through the preset number of access probes, after completing one access probe sequence and waiting for a separate random time (RS), the second access probe sequence and the second access probe sequence are different. We will start together.

However, since the ALOHA method also transmits data in a contention mode, a collision occurs inevitably between data transmitted from a terminal, and thus, there is a problem in that unnecessary data is transmitted during a collision. Of course, in order to solve this problem, although the base station can inform the contention state and control information to the terminal using a forward channel (forward link), this is a channel encoding technique or interleaving (interleaving) in order to successfully transmit a lot of data Since a large amount of time delay is generated, it is not effective when transmitting a long data such as a reverse common channel, and also reduces forward capacity.

In addition, there is a method of using a plurality of preamble signatures to improve the acquisition probability of the preamble. The preamble signature is a symbol for modulating a common spreading code used for a preamble transmitted for a reverse common channel, and orthogonality is maintained between the preamble signatures. In the case of transmission, the signals can be captured without interference.

However, in the data transmission method of the ALOHA protocol using the conventional code division multiple access scheme as described above, even if a large amount of data is transmitted through the reverse common channel by sufficiently setting the length of the preamble, the reverse common channel is stable by performing code synchronization and tracking. There is a feature that enables stable data transmission in.

However, while the preamble is a signal transmitted to establish the synchronization of the code, it is relatively less important than the actual data to be transmitted, and the length of the preamble becomes longer than the actual data length, and thus the transmission efficiency is increased. It will waste a lot of resources.

On the other hand, the method of notifying the race state and the control information to the terminal by using the forward channel (forward link) in the real-time processing is difficult, it is not effective when applied to the case that is actually transmitted for a short time, such as the reverse common channel.

At the same time, the above-described method cannot accommodate packet data having various characteristics, and a complicated structure operated in association with a higher protocol has difficulty in realizing a hierarchical structure of a physical layer.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem. According to a characteristic of data to be transmitted through a reverse common channel, a base station receives only a preamble and transmits a preamble by randomly selecting one of pre-allocated preamble signatures, thereby acquiring initial synchronization. Then, the preamble signature is notified to all terminals to confirm whether the preamble signatures transmitted by the corresponding terminals are captured. At this time, the terminals transmitting the captured preamble signatures transmit necessary data and are not captured. The UEs that transmit the preamble signature newly select a random time and a corresponding preamble signature and retransmit the preamble to reduce unnecessary data transmission, thereby reducing interference signals, thereby improving network efficiency, and performing fast retransmission using only the preamble. To be able to quickly access the appropriate power level as to provide a random access apparatus and method for a reverse common channel in a time delay characteristic is excellent becomes a code division multiple access method.

Accordingly, according to the random access device and method of the reverse common channel in the code division multiple access scheme according to the present invention, when transmitting a preamble that is premodulated by the preamble signature, the elements of the subsets of the preamble signatures classified according to traffic characteristics are preferentially transmitted. By arbitrarily selecting, packets of various characteristics can be efficiently operated. In addition, the base station performs initial synchronization on all useful preambles, and then informs all terminals of the preamble signature from which the initial synchronization has been acquired using the forward common channel, and whether the terminals transmitting the preambles have captured the preamble sent by the base station. Make sure to check. The UEs that transmit the captured preamble signatures transmit data using the inferred power level by using the power consumed in the preamble transmission, and the UEs that transmit the non-captured preamble signatures have an arbitrary time and a corresponding preamble. Select a new signature, determine the power level using the power level of the previous preamble, the current forward path loss, and the interference signal level transmitted from the base station, and retransmit the preamble to reduce unnecessary data transmissions and reduce the interference signal. By improving efficiency and performing fast retransmissions using only the preamble, it is possible to quickly access the appropriate power level, thereby ensuring excellent time delay characteristics.

1 is a process diagram of ALOHA data transmission using a reverse common channel in a code division multiple access scheme according to the prior art;

2 is a diagram illustrating a network configuration of a code division multiple access method to which the present invention is applied;

3A is a functional block diagram of a terminal and a base station in a random access device of a reverse common channel in a code division multiple access scheme according to the present invention;

3B is a block diagram of a transmission resource determining unit of FIG. 3A;

4A illustrates an operation of a random access device of a reverse common channel in a code division multiple access scheme according to the present invention;

4B is a diagram illustrating an operation of a random access device of an uplink common channel using a mini slot in a code division multiple access scheme according to the present invention;

5 is an exemplary diagram of an interference signal level due to a reverse common channel in a code division multiple access scheme according to the present invention;

6 is a flowchart illustrating a connection between a terminal and a base station of an arbitrary access device according to the present invention;

7 is a flowchart illustrating a connection control of a terminal according to the present invention;

Fig. 8 is a flowchart of connection control of a device station according to the present invention.

<Description of the code | symbol about the principal part of drawing>

100: terminal 110: transmission resource determination unit

111: signature receiver 112: signature selector

113: slot selection unit 114: power determination unit

120: preamble transmitter 130: transmission signal selector

140: terminal RF signal processing unit 150: acquisition confirmation signal receiving unit

160: transmission determining unit 170: terminal data processing unit

180: terminal data transmitter 200: base station

210: base station RF signal processing unit 220: initial synchronization unit

230: acquisition status determination unit 240: acquisition confirmation signal transmission unit

250: base station data transmission and reception unit

In the code division multiple access method according to the present invention for achieving the above object, the random access device and method of the reverse common channel, the base station performs the code initial synchronization for all useful preamble signature, and whether or not to capture the preamble signature All terminals are informed through a forward common channel, and the terminal selects a preamble signature corresponding to a characteristic of data to be transmitted, modulates the preamble, transmits the signal, and captures a preamble signature transmitted through the common channel from the base station. When the received preamble signature is captured, data is transmitted at an appropriate power level. If the transmitted preamble signature is not captured, a new preamble signature and time are arbitrarily selected to retransmit the preamble.

Hereinafter, a random access device of a reverse common channel in a code division multiple access method according to the present invention will be described with reference to the drawings.

2 is a block diagram of a general code division multiple access method for applying the present invention.

The terminal 100 generates data and transmits data through the reverse common channel, and performs a sign synchronization necessary for data reception using a preamble transmitted from the terminal 100 through the reverse common channel. A base station 200 that receives and serves as a relay, a CDMA network 300 that manages a plurality of the base stations 200 and 210 and performs interworking with other networks, and is linked with the CDMA network 300, Public Switched Telephone Network (PSTN) network 400 for connecting the terminal 100 to a general telephone subscriber, and the Internet interworking with the CDMA network 300 to connect the terminal 100 to a user of the Internet. Network 500 and the Public Switched Data Network (PSDN) network connected with the CDMA network 300 to connect the user to the terminal 100 and the data service support ( 600).

In the network configured as described above, the random access device for the reverse common channel according to the present invention performs the code synchronization of the preamble with respect to all the preamble signatures transmitted from the plurality of terminals to the respective base stations 200 through the reverse common channel. If the synchronization is acquired, further includes a capture acknowledgment signal transmitting means for informing the real-time through the common channel common to the acquisition confirmation signal corresponding to the captured preamble signature in real time,

Acquisition acquiring signal receiving means for receiving an initial synchronization acquisition acknowledgment signal of each preamble signature transmitted from the base station through a forward common channel; Based on the acknowledgment signal received by the acquiring acknowledgment signal receiving means, the terminals that have acquired the preamble signature transmitted by the acknowledgment signal transmit data afterwards. The terminal further includes transmission determining means for newly reselecting and setting the power level of the terminal to retransmit the preamble.

3A is a functional block diagram of a terminal and a base station in a random access device of a reverse common channel in a code division multiple access scheme according to the present invention.

The terminal 100 randomly selects a preamble signature corresponding to a traffic characteristic and a slot to transmit to generate a data to transmit and transmits the preamble, and uses a forward path loss, an interference signal level transmitted from a base station, and the like to transmit the preamble. A transmission resource determiner 110 for determining power, a preamble transmitter 120 for generating and transmitting a preamble signal using a transmission slot, a preamble signature, a power level, etc. determined by the transmission resource determiner 110, and the A transmission signal selector 130 for selecting a signal to be transmitted from a preamble and data generated by the preamble transmitter 120 using the acquisition confirmation signal transmitted from the base station 200, and the transmission signal selector 130 The selected signal is converted into an RF signal and transmitted to the base station 200 through a wireless channel, and to the base station 200. Whether the preamble signature is received from the terminal RF signal processing unit 140 and the baseband acquisition confirmation signal transmitted from the terminal RF signal processing unit 140. Enable the transmission resource determination unit 110 by using the acquisition confirmation signal receiver 150 for acquiring a signal and whether the transmission preamble signature confirmed by the acquisition confirmation signal receiver 150 is acquired, and the transmission signal selector ( A transmission determining unit 160 for outputting a signal for switching to 130; and a terminal data processing unit 170 for checking whether data is transmitted from the transmission determining unit 160 and enabling the data to be transmitted; After receiving the data to be transmitted from the terminal data processor 170, the code according to the preamble signature is selected and spread out. It consists of a data transmission terminal 180 to output to the transmission signal selection section 130.

Here, the transmission resource determining unit 110, the signature receiving unit 111 for receiving and storing information on the preamble signature assigned according to the traffic characteristics transmitted through the common channel from the base station, and the characteristics of the generated data and higher A signature selector 112 that selects a preamble signature in a random manner from among the corresponding preamble signatures by classifying traffic characteristics in consideration of the requirements of the layer, and a slot selector that randomly selects a slot to be transmitted in a random manner ( 113) and a power determination unit 114 for determining the power of the preamble to be transmitted through open loop power control in consideration of the interference signal level of the base station, the forward path loss, and the previously transmitted preamble power level. It is configured to include.

The power determination unit 114 is configured to determine the power level in consideration of the interference signal level of the base station transmitted through the common channel from the base station, the forward path loss, and the power level transmitted from the previous preamble.

The preamble transmitter 120 spreads and transmits a preamble signature using a common spread spectrum code by using the transmission slot, the preamble signature, and the power level determined by the transmission resource determiner 110. Two common spreading codes are used to generate a complex spread spectrum signal.

The acquisition confirmation signal receiving unit 150 receives the acquisition confirmation signal using a code used for the forward common channel and a code corresponding to the transmitted preamble signature.

In addition, the transmission determiner 160 enables the transmission resource determiner 110 by using the capture preamble signature confirmed by the acquisition confirmation signal receiver 150, and transmits the transmission signal selector 130. Outputs a signal for switching data and a preamble signal.

The base station 200 receives the RF signal transmitted from the terminal 100, the base station RF signal processor 210 for transmitting the RF signal to the terminal 100, and a reverse common channel at the terminal 100. The initial synchronization unit 220 receives the preamble transmitted from the base station RF signal processing unit 210 and performs initial synchronization according to all useful preamble signatures, and checks whether the initial synchronization is performed from the initial synchronization unit 220. A capture determination unit 230 for determining and outputting the captured captured preamble signature and a capture confirmation signal corresponding to the captured preamble signature inputted from the capture whether or not the determiner 230; Input the acquisition confirmation signal transmission unit 240 outputting to the terminal 100 through the processing unit 210 and the time delay information of the multi-path obtained by the initial synchronization unit 220 The base station RF signal processing unit may generate a despread code using information about the captured preamble signature input from the acquisition determining unit 230 and transmit the data transmitted from the terminal 100 through a reverse common channel. And a base station data transceiver 250 that receives the input from the processor 210 through demodulation and channel decoding.

The initial synchronizer 220 may include a synchronizer configured to receive a preamble transmitted through the reverse common channel from the terminal 100 from the base station RF signal processor 210 and perform initial synchronization according to all useful preamble signatures; The time delay characteristic output unit which recognizes all the time delay characteristics corresponding to the captured preamble signature to the base station data transceiver 250 and prepares to receive data to be immediately transmitted, and the acquisition decision determiner 230. And a capture signal output unit for indicating the preamble signature.

The acquisition determining unit 230 informs the data transmission / reception unit 250 of the corresponding spread spectrum code using the captured preamble signature received from the initial synchronization unit 220 to receive data to be immediately transmitted. And a confirmation signal generator for generating a signal using only the captured preamble signature and outputting the signal to the acquisition confirmation signal transmission unit 240.

The acquisition confirmation signal transmission unit 240 sets an appropriate time to the preamble signature and transmits an acquisition signal only at a time corresponding to the captured preamble signature. An antipodal signal system (# 2) which sets a corresponding time to a preamble signature and transmits a capture signal at a time corresponding to all preamble signatures regardless of whether or not to be captured, and a corresponding orthogonal code to the preamble signature. An on-off signal system (# 3) for transmitting only a symbol corresponding to the captured preamble signature, and an orthogonal code to be assigned to the preamble signature, One of the antipodal signaling systems (# 4), which always transmits symbols corresponding to all preamble signatures, regardless of whether they are captured Selected is configured to transmit a confirmation signal. That is, any one of the four signal systems # 1-# 4 is adopted as the acquisition confirmation signal transmission scheme, and the acquisition signal is transmitted.

The acquisition acknowledgment signal transmission scheme includes a puncturing technique for a conventional forward common channel, a technique for dedicating a separate channel having orthogonality to another forward common channel, and maintaining orthogonality to another forward common channel. It selects one of the techniques of channel-dedicated channel and transmits it.

In addition, the base station 200 uses a reverse common channel through a packet access for transmitting short data, a channel reservation request for transmitting medium data, and a channel request for assigning a dedicated channel for transmitting large data. Identify the nature of the data to be transferred. All possible preamble signatures are classified and allocated according to the characteristics of data to be transmitted and broadcasted through a forward common channel so that all terminals can recognize them.

In order to access a packet transmitted from the base station, the terminal selects one of preamble signatures classified according to the length and transmission rate of data to be transmitted through packet access, transmits the preamble, and receives whether the preamble is transmitted from the base station. It decides whether to retransmit or transmit data, and when transmitting data, single or multiple frames that meet the frame structure of the reference unit are continuously transmitted, and the frames that failed to transmit are operated for packet access. Is done to re-run.

For the channel reservation request, the terminal randomly selects one of the preamble signatures allocated for the channel reservation, transmits the preamble in the same manner as the packet access, and performs an initial synchronization by using the preamble transmitted from the terminal at the base station. The preamble signature is informed to all terminals through a forward common channel, and the terminals that transmit the uncaptured preamble signature randomly select one of the preamble signatures allocated for channel reservation, determine a time slot to transmit, and retransmit the preamble. After transmitting the captured preamble signature, the terminal transmits data for channel reservation, and then attempts channel reservation by transmitting data for reservation, and after the base station correctly receives data for channel reservation transmitted from the terminal,It informs the terminals of whether the channel is reserved, reserved time and spread code, and transmission rate by using the general channel, and the corresponding terminals transmit data to be transmitted using the reserved time, spread code, and transmission rate. Closed loop power control is performed using a power control command transmitted through a forward channel. When the final frame is transmitted, channel reservation is canceled by including information indicating that data transmission is completed.

In order to change the channel reservation condition while using the reserved channel, the data for changing the channel reservation condition is transmitted at the same time as the packet access or the channel reservation request at the same time as the data transmission.

Hereinafter, the operation of the random access device of the reverse common channel in the code division multiple access method according to the present invention will be described.

As shown in FIG. 6, when data to be transmitted is generated by the terminal 100, the terminal 100 transmits a preamble to the base station 200, and the base station 200 performs initial code synchronization to transmit initial synchronization acquisition confirmation signals to all terminals. Accordingly, the terminal receives the initial synchronization acquisition confirmation signal and retransmits the preamble if the preamble transmitted by the terminal is not captured, and transmits the data if the preamble transmitted by the terminal is captured.

In operation of the terminal, as shown in FIG. 7, when data to be transmitted is generated (S101), a preamble signature corresponding to a traffic characteristic and a slot to be transmitted are arbitrarily selected to transmit a preamble (S102), and a forward path loss and a base station are performed. A transmission resource determination process of determining a power of a preamble to be transmitted is performed by using an interference signal level transmitted in S103.

Subsequently, a preamble is generated based on the resources determined in the transmission resource determination process, and the generated preamble is transmitted (S104). A preamble transmission process (S104) for generating and transmitting a preamble signal using a slot, a preamble signature, a power level, and the like determined in the transmission resource determination process is performed.

Thereafter, the base station receives the preamble acquisition confirmation signals broadcast to all terminals from the base station (S105) to confirm whether the preamble signature transmitted by the base station is captured (S106).

If the preamble transmitted by the acquisition signal is acquired during the acquisition confirmation signal reception process, the data is transmitted according to the form of the data to be transmitted, the data transmission process of selecting and spreading the code according to the preamble signature is carried out (S107). If the preamble transmitted by itself is not captured in the acquisition confirmation signal receiving process, the process of retransmitting the preamble is repeated (S108).

Meanwhile, the base station 200 controls the transmission of the preamble acquisition confirmation signal as shown in FIG. 8. First, an RF signal received from a terminal is received (S201), and an initial synchronization process (S202) of performing initial synchronization with respect to all received useful preamble signatures is performed.

Subsequently, the acquiring preamble signature is determined by checking whether the initial synchronization has been performed (S203), a capture acknowledgment signal transmission process (S204) generating a capture acknowledgment signal corresponding to the captured preamble signature, and outputting it to all terminals. Perform.

In addition, the multi-path time delay information obtained in the initial synchronization is input, a despread code is generated using the information on the acquired preamble signature, and ready to be received (S205). Receiving and processing the data transmitted through the process of transmitting and receiving through demodulation and channel decoding process (S206).

The above operation will be described in detail with reference to FIGS. 3 to 5 as follows. The terminal 100 enables the transmission resource determination unit 110 from the outside. In this case, the enabled transmission resource determination unit 110 generates a random set of preamble signatures according to characteristics of data to be transmitted. One method selects one preamble signature and randomly selects a slot to transmit at the same time. The preamble transmitter 120 spreads the preamble using a spread spectrum code commonly used using the preamble signature determined as described above to generate a preamble to be transmitted, and transmits the preamble in the selected transmission slot. In this case, the transmission signal selector 130 is connected to the preamble transmitter 120 and output to the terminal RF signal processor 140 to be transmitted to the base station 200.

Accordingly, in the base station 200, the RF signal processing unit 210 receives the preamble transmitted from the terminal 100 and outputs the preamble to the initial synchronization unit 220, and all the preamble signatures available to the initial synchronization unit 220. According to each of the initial synchronization is performed to output information for determining whether to capture as well as the transmission to the capture or not determiner 230. The acquisition determination unit 230 receives information corresponding to each preamble signature from the initial synchronization unit 220 to determine a captured preamble signature, and determines the acquisition confirmation signal transmission unit 240 and the base station data. Output to the transceiver 250. The acquisition confirmation signal transmitter 240 receiving the captured preamble signature generates a signal corresponding to the captured preamble signature through a forward common channel that can be confirmed by all terminals, and transmits the signal through the base station RF signal processor 210. Output to the terminal 100. The base station data transceiver 250 receives the preamble signature captured by the acquisition determining unit 230 and transmits data to be transmitted from the terminal 100 using a spread spectrum code corresponding to the captured preamble signature. Prepare to receive.

Meanwhile, the acquisition confirmation signal receiver 150 receiving the acquisition confirmation signal transmitted from the base station 200 through the forward common channel through the terminal RF signal processor 140 confirms whether the transmitted preamble signature is captured. It outputs whether or not this is confirmed to the transmission determining unit 160.

In this case, when it is confirmed that the transmitted preamble signature is captured, the transmission resource determining unit 110 and the preamble transmitting unit 120 are disabled, and the data transmitting unit 180 transmits the data by the terminal data processing unit 170. The spread spectrum is spread by using a spread spectrum code corresponding to the preamble signature that transmits the data, and outputs the spread signal to the transmission signal selector 130. The transmission signal selector 130 receives the preamble signature acknowledgment signal from the transmission determination unit 160, and connects a switch to an output of the data transmitter 180, through the terminal RF signal processor 140. The base station 200 transmits the data. Subsequently, the transmitted data is input to the base station data transceiver 250 through the base station RF signal processor 210 of the base station 200, and the base station data transceiver 250 uses the spread spectrum code previously confirmed. Through the demodulation and decoding process, data is recovered through the reverse common channel.

On the other hand, when it is confirmed that the preamble signature transmitted by the transmission determiner 160 is not captured, the transmission resource determiner 110 and the preamble transmitter 120 are enabled. That is, the transmission resource determining unit 110 newly selects one preamble signature in a random manner from a corresponding set of preamble signatures and randomly selects a slot to be transmitted at the same time. The reason for randomly selecting a slot to be transmitted is that if a preamble is not captured due to a collision, if a retransmission is performed after a predetermined time, the slot will be collided again. Similar to the initial preamble transmission, the preamble transmitter 120 generates a preamble by spreading the spectrum using a spread spectrum code commonly used using the preamble signature determined as described above, and generates a preamble in the selected transmission slot. Send it. In this case, the transmission signal selector 130 is connected to the preamble transmitter 120 to be output to the terminal RF signal processor 140 to be transmitted to the base station 200. This operation is repeated as described above, and the number of repetitions can be appropriately selected as a parameter for operation.

In FIG. 4, a packet access for transmitting short data having the same length is shown as an example of the operation of a random access device of a reverse common channel in a code division multiple access method.

First, in the exemplary diagram of the random access device operation of the reverse common channel in the code division multiple access method according to the present invention shown in FIG. 4, it is assumed that the frame period is 10 [ms] and one slot is 1.25 [ms]. There are eight transmission slots in one frame period. One slot transmits a time (1 [ms]) at which the preamble is transmitted and a reception ready and acquisition confirmation signal, and the terminal includes an inactive section (0.25 [ms]) which generates no signal. In addition, for the sake of simplicity, the case of two preamble signatures is considered, and only a case where only short data is generated is assumed. In addition, the data transmitted by the terminal through the reverse common channel is limited to 10ms in length.

The first slot begins to transmit the time (T ₀₎ from among the terminals that have data to transmit in the preceding three terminal randomly selects a transmission T ₀ in the slot. In this case, all three transmitted preambles are not captured. This is a case where all preambles select the same preamble signature, or when the power of one preamble does not become higher than a predetermined level than the power of other preambles, causing interference with each other. can see. At this time, since all preambles have not been captured, data is not transmitted, and new power levels, time slots, and preamble signatures are selected and retransmitted.

In different time slots T ₁ , two preambles are transmitted and captured, where each preamble determines the appropriate power level through open loop power control and transmits using different preamble signatures. . Thus, the terminals that transmitted the captured preamble will transmit data for a length of 10 [ms] in time slot T ₂ .

On the other hand, two preambles are also transmitted in the time slot T ₂ , and both preambles are captured. However, only one data is correctly received and the other shows that the transmission failed. Although two preambles transmit using the same preamble signature, the power of one preamble is much higher than the power of the other. The UEs, which have captured one preamble but transmit the preamble, determine that their own preamble has been captured and transmit data. The same operation is performed at a later time.

5 illustrates an interference signal level of the base station according to an exemplary diagram of an operation of a random access device of a reverse common channel in a code division multiple access method according to the present invention of FIG. 4. 5, the solid line shows the interference level by the random access device of the conventional reverse common channel, and the portion indicated by the dotted line shows the interference signal level by the random access device of the reverse common channel according to the present invention. The amount of reduction in the interference signal level by the random access device of the reverse common channel according to the present invention is shown.

As can be seen in Figure 5, the random access device of the reverse common channel according to the present invention by reducing a large amount of unnecessary data transmission to reduce the interference signal level to increase the overall capacity and the effect on the user using other channels Can be minimized, and retransmission can be performed in units of preambles, thereby enabling faster data transmission.

Hereinafter, a case in which short data having various data lengths is serviced through a packet access method using an operation similar to the above will be described. In this case, when the data length exceeds a certain level, since a dedicated channel request or a reservation request is required, the actual data length is an integer multiple of the existing frame unit, and the type is limited. As an example of this, a data length of 10 [ms], 20 [ms], and 40 [ms] is transmitted through a packet access method, and when the data length is larger than this, a method for requesting a dedicated channel allocation or requesting a channel reservation is required. Should be selected.

First, the preamble signature allocated for packet access needs to be reclassified according to the length of data to be transmitted and recognized by the base station to all terminals. It is preferable to assign and operate a large number of preamble signatures to the busy traffic using the amount of traffic according to the data length. And, the terminal to transmit data in the reverse common channel to determine the characteristics of the data traffic, using the length and transmission rate of the data to be transmitted, and if the data is to be transmitted through the packet access preamble signature corresponding to this The preamble is transmitted. For example, UEs wishing to transmit data of 40 [ms] transmit a preamble using a packet access preamble signature of 40 [ms], and at this time, 40 [ms] data is plural on the basis of the existing data transmission unit. Frames will be sent continuously. If a frame that fails to be transmitted is continuously retransmitted among the continuously transmitted frames, the preamble signature is selected according to the data characteristic to be retransmitted in the same manner as described above, and the preamble is transmitted.

Next, when it is necessary to temporarily reserve a channel for transmitting medium length data, an operation of requesting channel reservation using a reverse common channel will be described. First, the terminal 100 transmits the required channel reservation information and the identification number of the terminal through the packet access. When the packet access is transmitted, one of the preamble signatures allocated for the channel reservation is selected to transmit the preamble, and the base station 200 receives a signal indicating whether to acquire the initial synchronization and transmits data for channel reservation. In this case, since the data required for channel reservation is relatively smaller than the frame basic unit, the data can be transmitted in a frame structure rather than the frame basic unit, and the length of the channel reservation data to be transmitted by the terminal can be known by the preamble signature captured by the base station. . Of course, this method is identical to the operation used for the packet access.

Once the base station 200 receives the data for channel reservation correctly, the base station 200 informs the corresponding terminals of whether the channel is reserved, the reserved time and spread code, and the transmission rate by using the common channel. Data to be transmitted is transmitted using the reserved time, spread code, and transmission rate. At this time, the base station transmits a power control command signal using a forward common channel for the reserved terminal and performs closed loop power control accordingly. If the channel reservation condition is to be changed during the channel reservation, the channel reservation condition to be changed is transmitted in the same manner as the method for transmitting the preamble for the initial channel reservation as described above. When the channel reservation is completed, the base station allocates a predetermined field (filed) to the last frame of the data transmitted from the terminal to inform the base station, releases the reserved channel and time by using the reservation information determined in the channel reservation, and all Notify the terminal.

The method of channel reservation using the medium length data may be used in an application field such as a packet voice service in which future services are expected.

Meanwhile, an operation for requesting a dedicated channel for a service such as a long data or a voice signal uses a method similar to the above channel reservation. First, one of the preamble signatures allocated for the dedicated channel is randomly selected. The preamble is transmitted, the base station 200 receives a signal indicating whether to acquire the initial synchronization, and transmits data for dedicated channel allocation. The base station 200 receives information on whether a dedicated channel is allocated and spread code, and then transmits and receives data using the dedicated channel. Even in this case, as in the channel reservation request, data can be transmitted without being limited to the frame length of the basic unit, and closed loop power control can be easily implemented by allocating a dedicated channel in both the reverse direction and the forward direction.

According to the random access device and method of the reverse common channel in the code division multiple access method according to the present invention described above, the preamble signatures are allocated according to the characteristics of the data, so that the terminals can randomly select one of the preamble signatures according to the data to be transmitted. By selecting and transmitting a preamble, it is possible to use various types of reverse common channels such as a channel request requesting a dedicated channel allocation, a packet access for transmitting short data, and medium sized data. In addition, the base station performs initial synchronization on all possible preambles, and then informs all the terminals of the preamble signature from which the initial synchronization has been acquired by using a forward common channel, and whether the terminals transmitting the preamble capture the preamble sent by the base station. By checking and transmitting the data to be transmitted or retransmitting the preamble accordingly, it can reduce unnecessary data transmission, reduce the interference signal, improve network efficiency, and perform fast retransmission by using only the preamble, so that the appropriate power level can be quickly accessed. Characteristics can be obtained.

Claims (31)

A wireless terminal apparatus for transmitting data to a base station through a common channel using a code division multiple access method, Preamble generating means for generating a preamble signal using one preamble signature selected from a plurality of available preamble signatures; Data generating means for generating data to be transmitted; And And control means for controlling the transmission of the data to the base station when the preamble is transmitted to the base station, when the acquisition confirmation signal indicating acquisition of the transmitted preamble signature is received from the base station. The method of claim 1 wherein said control means If the acquisition confirmation signal indicating acquisition of the transmitted preamble signature is not received, the preamble generating means selects a new preamble signature and uses the selected new preamble signature as the selected one of the preamble signatures. A wireless terminal device for controlling to transmit to a base station at a predetermined time. The method according to claim 1 or 2. The preamble is transmitted using a connection slot selected from among the available access slots. The method of claim 3, wherein the preamble generating means, Under the control of the control means, a transmission resource for arbitrarily selecting the selected preamble signature corresponding to the traffic characteristic and a slot to be transmitted, and determining the power of the preamble to be transmitted using a forward path loss, an interference signal level transmitted from the base station, and the like. Decision unit; And And a preamble generator configured to generate a preamble signal using a transmission slot, a preamble signature and a power level determined by the transmission resource determiner. The method of claim 1 wherein said control means And a transmission signal selection unit for selecting a signal to be transmitted between the preamble generated by the preamble generation means and the data from the data generation means in response to the acquisition confirmation signal transmitted from the base station. 6. The apparatus according to claim 5, wherein said data generating means A terminal data processing unit configured to check whether data is transmitted from the transmission determining unit and to enable and to transmit data to be transmitted; And And a terminal data transmitter which receives the data to be transmitted from the terminal data processor, spreads the code according to a preamble signature, and outputs the code to the transmission signal threshold. The method of claim 3, wherein the transmission resource determination unit, Signature receiving means for receiving and storing information on the preamble signature assigned according to the traffic characteristic transmitted through the common channel from the base station; Signature selection means for classifying traffic characteristics in consideration of the characteristics of the generated data and the requirements of a higher layer, and selecting a preamble signature from a corresponding preamble signature in a random manner; Slot selecting means for randomly selecting a slot to be transmitted in a random manner; And And a power determining means for determining the power of the preamble to be transmitted according to a predetermined criterion in consideration of the interference signal level of the base station, the forward path loss, and the previously transmitted preamble power level. A base station receiving data from a wireless terminal device through a common channel by using a code division multiple access method Receiving a preamble transmitted through the reverse common channel from the terminal and using all available preamble signatures to determine the captured preamble signature, and generates an acquisition confirmation signal corresponding to the captured preamble signature to output to the terminal device Preamble signature capturing means; And And a base station data transceiver configured to generate a reverse spread code using information on the preamble signature captured by the preamble signature acquiring means and to receive data transmitted next from the terminal through a reverse common channel. The method of claim 8, wherein the preamble signature capturing means, A synchronizer configured to transmit preambles transmitted through a reverse common channel by the terminal to perform initial synchronization according to all available preamble signatures; A time delay characteristic output unit for recognizing all the time delay characteristics corresponding to the captured preamble signature to the base station data transceiver to prepare to receive the immediately transmitted data; And And a capture confirmation signal output unit configured to output the captured preamble signature. 9. The apparatus of claim 8, wherein the preamble signature capturing means A spread spectrum code generation unit which notifies the corresponding data spreading code to the data transmitting / receiving unit by using the captured preamble signature to prepare to receive data to be immediately transmitted; And a capture confirmation signal generator for inputting the captured preamble signature from the capture confirmation signal output unit to acquire an additional capture confirmation signal indicative of the captured preamble signature. The method of claim 10, wherein the acquisition confirmation signal generation unit, And a base station configured to set a corresponding time to the preamble signature and output an acquisition confirmation signal as an on-off signal system that transmits an acquisition signal only at a time corresponding to the captured preamble signature. The method of claim 10, wherein the acquisition confirmation signal generation unit, An antipodal signal system configured to set a corresponding time on a preamble signature and to transmit a capture signal at a time corresponding to all preamble signatures regardless of whether the signal is captured or not; Base station. The method of claim 10, wherein the acquisition confirmation signal transmission unit, And a corresponding orthogonal code assigned to the preamble signature as a symbol to be transmitted, and outputting an acquisition acknowledgment signal as an on-off signal system for transmitting only a symbol corresponding to the acquired preamble signature. The method of claim 10, wherein the acquisition confirmation signal transmission unit, It is configured to output a capture acknowledgment signal as an antipodal signal system that assigns a corresponding orthogonal code to a preamble signature and sets it as a symbol to be transmitted, and always transmits a symbol corresponding to all preamble signatures regardless of acquisition. Base station. In a random access method in which a plurality of terminals transmit data through a common channel by using a code division multiple access method, A) each terminal, when the data to be transmitted is generated, A) step of randomly selecting each of the preamble signature and the connection slot and transmits each preamble to the base station; B) the base station performs initial synchronization on all preamble signatures transmitted from the terminal and transmits preamble acquisition confirmation information to all terminals; After receiving the preamble acquisition confirmation information transmitted from the base station, the terminal receiving the preamble signature transmitted by the base station performs data transmission, and at the terminal where the preamble signature transmitted by the base station is not captured, the preamble signature and the slot are randomly reset. The random access method of the reverse common channel in the code division multiple access method comprising the step C) of retransmitting the power control preamble by a predetermined amount. The method of claim 15, wherein the terminal A) A transmission resource determination step of randomly selecting a preamble signature corresponding to a traffic characteristic and a connection slot to be transmitted to generate data to be transmitted and transmitting the preamble, and determining power of a preamble to be transmitted in a predetermined method; And And a preamble transmission step of creating and transmitting a preamble signal using a slot, a preamble signature, a power level, and the like determined in the transmission resource determination step. 17. The method of claim 16, wherein determining the transmission resource A signature information receiving step of receiving and storing information on an allocated preamble signature according to traffic characteristics transmitted from a base station through a common channel; A traffic characteristic determination step of classifying traffic characteristics in consideration of the characteristics of the generated data and the requirements of the upper layer; A preamble signature selection step of selecting one preamble signature among the available preamble signatures in a random manner; An access slot selection step of arbitrarily selecting an access slot to be transmitted in a random manner; And The random access method of the reverse common channel in the code division multiple access scheme comprising the step of determining the power of the preamble to be transmitted through the open loop power control. The method of claim 17, wherein the preset method comprises: Interference signal level of the base station transmitted via the common channel from the base station; Forward path loss; And The random access method of the reverse common channel in the code division multiple access method, characterized in that for adjusting the power level as much as the predetermined amount in consideration of the power level transmitted from the previous preamble. The method of claim 16, wherein step A) Random access of a reverse common channel in a code division multiple access scheme using a transmission slot, a preamble signature and a power level determined in the transmission resource determination step, and spreading and transmitting a preamble signature using a common spread spectrum code Way. 20. The method of claim 19, wherein step A) A random access method of a reverse common channel in a code division multiple access scheme, characterized in that a complex spread spectrum signal is generated using two common spread spectrum codes. The method of claim 16, wherein step C) The random access method of the reverse common channel in the code division multiple access method, characterized in that the acquisition acknowledgment signal is received using the code used for the forward common channel and the code corresponding to the transmitted preamble signature. 16. The reverse common channel in the code division multiple access scheme according to claim 15, wherein the terminal repeats steps A), B), and C) by a predetermined number of times in the terminal where the preamble signature transmitted by the terminal is not captured. Random connection method of. The method of claim 15, wherein step B) An initial synchronization step of receiving, by the terminal, a preamble transmitted through a reverse common channel and performing initial synchronization according to all available preamble signatures; An acquiring determination step of determining whether to acquire an initial synchronization from the initial synchronization step and determining and outputting the captured preamble signature; A capture confirmation signal transmission step of generating a capture confirmation signal corresponding to the captured preamble signature inputted from the capture decision step and outputting it to the terminal; And Receives multi-path time delay information obtained in the initial synchronization step, generates a despread code using information on the captured preamble signature inputted from the acquisition determination step, and transmits a despread code to the terminal through a reverse common channel. And a base station data transmission / reception step of receiving the transmitted data through demodulation and channel decoding, and the like. The method of claim 23, wherein the initial synchronization step, Receiving, by the terminal, a preamble transmitted through a reverse common channel from the base station RF signal processing step and performing initial synchronization according to all useful preamble signatures; A data reception preparation step in which all the time delay characteristics corresponding to the acquired preamble signature are recognized in the base station data transmission / reception step and ready to receive data to be immediately transmitted; And Random access method of a reverse common channel in a code division multiple access method comprising the step of informing the acquisition whether or not the captured preamble signature. The method of claim 23, wherein the determining whether to capture, Using the captured preamble signature received from the initial synchronization step, notifying the corresponding data spreading code to the data transceiver to prepare to receive data to be immediately transmitted; And And generating a signal using only the acquired preamble signature and outputting the signal to the acquisition acknowledgment signal transmitting step. 24. The method of claim 23, wherein sending a capture confirmation signal comprises: An on-off signal system for setting a corresponding time in a preamble signature and transmitting a capture signal only at a time corresponding to a captured preamble signature; An antipodal signal system that sets a corresponding time to the preamble signature and transmits an acquisition signal at a time corresponding to all preamble signatures regardless of whether or not to be captured; An on-off signal system for assigning a corresponding orthogonal code to a preamble signature as a symbol to be transmitted and transmitting only a symbol corresponding to the captured preamble signature; And Acquisition acknowledgment signal by selecting an orthogonal code to the preamble signature and setting it as a symbol to be transmitted, and selecting an antipodal signal system that always transmits a symbol corresponding to all preamble signatures regardless of acquisition. Random access method of the reverse common channel in the code division multiple access method characterized in that the transmission to the system. 27. The system of claim 26, wherein the acquisition confirmation signal transmission scheme is: A method of puncturing a conventional forward common channel; Dedicating a separate channel having orthogonality to another forward common channel; And The random access method of the reverse common channel in the code division multiple access method, characterized in that the transmission is selected from one of the methods for dedicating a channel that does not maintain orthogonality to other forward common channel. The method of claim 15, wherein the base station A channel request requesting dedicated channel allocation to transmit large data; Packet access to send short data; And It is a reservation request for transmitting medium sized data. The characteristics of data to be transmitted through the reverse common channel are distinguished, and the corresponding preamble signature is appropriately allocated to transmit the information through the forward common channel so that all terminal devices can recognize it. Random access method of the reverse common channel in the code division multiple access scheme. The method of claim 28, wherein in packet access: The random access method of the reverse common channel in the code division multiple access scheme, characterized in that the preamble signature allocated to the packet access for transmitting short data is further subdivided according to the data transmission length. 29. The method according to claim 28, wherein for the channel reservation request, A terminal randomly selects one of the preamble signatures allocated for channel reservation and transmits the preamble in the same manner as the packet access. The base station performs initial synchronization using the preamble transmitted from the terminal to inform all the terminals of the captured preamble signature through the forward common channel. The terminals transmitting the uncaptured preamble signature randomly select one of the preamble signatures allocated for channel reservation, determine a time slot to transmit, and retransmit the preamble. After transmitting the captured preamble signature, the terminal transmits data for channel reservation, and then attempts channel reservation by transmitting data for reservation. The base station accurately receives the data for channel reservation transmitted from the terminal, and informs the terminals of the channel reservation, the reserved time and spread code, and the transmission rate using the common channel. Applicable terminals transmit data to be transmitted using a reserved time, spreading code, and transmission rate, perform closed loop power control using a power control command transmitted through a forward channel, and The random access method of the reverse common channel in the code division multiple access method, characterized in that when the last frame is transmitted, the channel reservation is canceled by including information indicating that data transmission is completed and transmitted together with the data. The method of claim 30, wherein the channel reservation condition is changed during use of the reserved channel. The random access method of the reverse common channel in the code division multiple access method, characterized in that for transmitting the data for the channel reservation condition changes in the same manner as the packet access or the channel reservation request at the same time as the data transmission.