KR100705916B1 - A preamble code receiver for CDMA telecommunication system and the operation method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for an independent cell radius setting and operation thereof, and a method of operating the same, in a preamble code receiver of a code division multiple access communication system.

A preamble receiver of a code division multiple access system according to the present invention receives n inputs and a despreading factor, and is set in association with independent cell radii set for each cell, and supports n discs supporting minimum radii. A reading data buffer; A combining processor in which the number of the n spreading buffers to be combined is determined according to a combination of the number of radii and signatures for one cell radius or k cells having two or more different cell radii; It is characterized by.

Preamble, Multiple Antennas, Multiple Cells

Description

A preamble code receiver for CDMA telecommunication system and the operation method

1 is a block diagram of a preamble code receiver supporting a minimum cell radius according to the present invention.

2 is a block diagram of an entire preamble code receiver supporting multiple cells and cell radius according to the present invention.

Figure 3 is a block diagram showing an example of the combination of the spreading data buffer for supporting multiple cells and cell radius according to the present invention.

4 is a cell diagram illustrating a conventional multi-cell and cell radius.

5 is a cell diagram illustrating multiple cells and cell radius according to the present invention;

6 is a flowchart illustrating a method of operating a preamble receiver according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

101 ... despreading factor generator 110 ... preamble receiver

111 ~ 11n ... Despreading Buffer 120 ... Combination Processor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for an independent cell radius setting and operation thereof, and a method of operating the same, in a preamble code receiver of a code division multiple access communication system.

The preamble code currently used in the code division multiple access system is a code obtained by spreading a series of signatures into a scrambling code, and a receiver receiving the preamble code uses a matched filter and a correlator. The sequence of signatures to be spread is one, and the spreading is done sequentially per bit of the signature. Thus, the size of the register needed for despreading is the spread PN code length per bit of the signature, which is the definition for despreading at a point within a fixed cell. However, in the real asynchronous IMT-2000 system, the RACH preamble code has 16 signatures, and the signature spreading method is different from the above description.

The 16 signatures are shown in Table 1.

In the signature spreading method, since the signature is spread with a 4096 scrambling code having 256 repetitions, the register size required for despreading in the preamble receiver is 4096.

This content is expressed as a formula as follows.

Signature: Csig, s (i) = Ps (i modulo 16), i = 0, 1,... , 4095

Scrambling code: S _{c-acc, n} (i) = c _{long, 1, n} (i), i = 0, 1,... , 4095

, k = 0, 1, 2, 3, …, 4095Preamble Codes:

, k = 0, 1, 2, 3,... , 4095

As shown in the above equation, the 4096 scrambling code requires 16 sequences of 256 repetitions, and 16 types of signatures require 16 times more hardware resources than existing multiple access systems. .

Therefore, in order to despread such a frame, even if one signature is found, since the round trip delay is different according to the cell radius set in the system, the hardware size is inevitably based on the maximum settable cell radius. In addition, since 16 signatures exist, resource waste in the area with a small cell radius such as the city center is inevitable.

To overcome this, a method of variably adjusting the number of signatures required for despreading in the preamble receiver according to the cell radius has been proposed. This method is based on supporting up to 16 signatures based on the smallest cell radius (5km) that can be supported on the system. Therefore, using a signature receiver responsible for one signature search, a preamble receiver for searching for [cell radius 10km, eight signatures], [cell radius 20km, four signatures], and [cell radius 40km, two signatures] is searched. will be.

This method can increase the efficiency by modifying the hardware structure to 2n times the minimum cell radius, but has a limitation that the supportable cell radius is limited. The actual cell radius of the system to be operated is determined by field survey to determine various external conditions to determine the most suitable cell radius. Therefore, if the type of cell radius that can be set according to the hardware structure does not vary, there is a limit in operating the most optimal cell.

An object of the present invention is to provide a preamble receiver and a receiving method with variable usability and expandability.

Another object of the present invention is to provide an optimal operating environment by enabling the cell radius that can be supported according to actual cell determination to be set independently for each cell.

It is still another object of the present invention to support multiple antennas so that preambles from multiple cells can be simultaneously received according to a system environment.

A preamble receiver of a code division multiple access system according to the present invention for achieving the above object is

A preamble code receiver of a code division multiple access communication system,

N despreading data buffers which receive input and a despreading factor of a received signal and are set in association with each independent cell radius and support a minimum radius;

A combining processor in which the number of the n spreading buffers to be combined is determined according to a combination of the number of radii and signatures for one cell radius or k cells having two or more different cell radii; It is characterized by.

In detail, the spreading factor is determined according to an antenna configured for system operation, a scrambling code for cells to be searched through each antenna, and a preamble search radius and the number of signatures of individual cells.

Specifically, the spreading data buffer is characterized by being divided into each cell and signature.

In detail, the number of despreading data buffers that are set in association to search for the signature one may vary according to a cell radius.

Specifically, the combination of the number of cell radii and the number of search signatures may be equal to or smaller than the number of spreading data buffers.

Specifically, the cell radius is determined in units of the minimum cell radius.

Specifically, the combining processor determines the number of despreading buffers to be combined according to the number of radii and signatures for one cell radius or k cells having two or more different cell radii. do.

In detail, the combined spreading buffer may be allocated by the number of minimum cell radius units.

A method of operating a preamble code receiver of a multiple access communication system according to another embodiment of the present invention,

Identifying a number of antennas set to support multiple cells and identifying a cell search radius independently supported for each cell;

Checking the scrambling code for each antenna and determining the number of signatures for each antenna;

Setting an internal structure including a size of a de- spreading buffer of a preamble receiver according to the number of antennas, an independent cell search radius, a scrambling code, and a number of signatures;

According to the configuration of the preamble receiver, the preamble receiver is characterized in that it comprises the step of reporting the search results confirmed for each cell.

Preferably, after the basic driving unit time of the preamble receiver has elapsed, it is checked whether there is a setting change for searching, and when there is a change, the internal structure including the size of the despreading buffer of the preamble receiver according to the changed item. And resetting only some items.

Hereinafter, an operation according to a preamble receiver according to the present invention will be described with reference to the accompanying drawings.

1 is a block diagram illustrating a preamble receiver according to the present invention, and is a block diagram showing a configuration for detecting one signature at a minimum cell radius.

As shown in FIG. 1, the result of multiplying a scrambling code by a signature is stored in a 16-chip unit size in a single chip of 128 chips in accordance with a minimum cell radius. a preamble spreading factor generator 10 generating a final preamble spreading factor by combining a chip with a predetermined phase rotation factor; A data storage unit 20 for dividing the on-time and half-time data into a multiple of a clock faster than a required data reference clock to shift the antenna input data into a reference clock; A spreading unit 30 for performing preamble spreading by alternately multiplying the spreading factor for each section 8 times in units of half chip with respect to the data stored in the data storage unit 20; An adder 40 configured to add a plurality of adders to match and filter the output values of the spreading units in units of 16 chips; Each round trip delay position includes an accumulator 50 that accumulates the output value of the adder 40 until the final preamble spreading is completed.

The preamble spreading factor generator 10 defines a 128-chip single buffer 11 that stores a result of multiplying a scrambling code and a signature according to a minimum cell radius, and defines a stored preamble spreading factor. A preamble factor selector 13 which continuously selects the factors stored in the buffer in predetermined units at a clock speed that is faster than the reference clock according to the preamble factor; And a phase rotation factor generator 14 for generating a phase rotation factor.

The despreading unit 30 includes a plurality of multiplexers 31 for selecting one of on-time data and half-time data faster than the reference clock; It consists of a plurality of multipliers 32 which multiply the value provided via the multiplexer 31 and the preamble spreading factor faster than the reference clock for each bit.

The part of generating the preamble spreading factor is a multiplication of the scrambling code and the signature and the length is 4096. In addition, each time the code is generated, it is rotated in the constellation and its sign is changed.

In the present invention, the results of the scrambling code and the signature multiplier 11 are shifted and stored in the single buffer 11 for each chip. The interval is set to 128 chips in accordance with the minimum cell radius (eg, 5 km) to be supported by the preamble receiver. At this time, the single buffer 11 is largely divided into eight parts in units of 16 chips. The reason is to make the most of the chip x 16 clock (1 / (3.84e6 * 16) sec) used as the system clock of the present invention. In other words, by processing the 128-chip period corresponding to the on-time or half-time for each 16-chip unit at a time for each clock, the chip clock is divided as much as possible (2 x 8 chip x 16 clocks). This is because preamble spreading is possible. The multiplication result of the scrambling code and the signature stored in the single buffer 11 is selected by the selector 13 in units of 16 chip sections.

A phase rotate factor is applied to the value selected by the selector 13 to be combined for each bit to produce the final preamble spreading factor.

Data input through the antenna is divided into on-time data and half-time data, shifted every chip, and stored in the data storage unit 20 configured as a single buffer.

Here, the internal structure for despreading has the same structure by dividing the i-channel (i_ch) portion and the q-channel portion (q_ch), respectively. After being stored in the buffer for the first 16 chips, the actual despreading process begins. The chipx1 clock (1 / (3.84e6) sec) is used as a selection terminal for on-time and half-time data, and is processed in half cycles.

For the on-time and half-time data provided alternately in half-chip units, in order to find the minimum radius considering the round trip delay, the spreading factor is multiplied by the interval eight times for each interval. Perform preamble spreading. In this case, in order to search for a preamble for a point, 4096 despreading operations are required. During the initial 128 chip period, the entire chipx16 clock is not used for each of the i-channel and q-channels because the entire search radius is still in progress. For the same reason, since the preamble spreading ends after a small round trip delay after the spreading process for 4096 chips, the entire chipx16 clock section is not used.

Through this process, the data during the 16 chip periods despread at once are merged into one through the adders 41, 42, 43, and 44 having a matched filter structure. Initially through eight 8-bit adders (41), followed by four 9-bit adders (42), two 10-bit adders (43), and one 11-bit adder (44), followed by i or q 12 Bit value, and this process exists for each of i-channel and q-channel, respectively.

The calculated values should be accumulated until the end of the final preamble despreading at that point. Therefore, an accumulator of 20 bits is required for each channel for 4096 length addition processing. In this embodiment, an accumulator 51 of 40 bits which simultaneously processes i-channel and q-channel is used.

The intermediate values until the final result value for the preamble search interval should be stored in the memory. In accordance with the 4096 length spreading period, the i-channel and q-channels are combined to make the bit size 52 of the memory 40 bits. Since there are 128 position-specific spreading values in consideration of the round trip delay for each on-time and half-time, an address having a length of 256 is required.

In the process of reading and writing data in the middle of memory, the chipx16 clock is not always used as the round trip delay is considered. Memory input / output is limited according to the progress of the search process, so the most optimal operation is possible.

2 is a block diagram of an entire preamble receiver according to an embodiment of the present invention.

Referring to FIG. 2, the preamble receiver 110 is a receiver having a minimum cell radius support structure, and receives a received signal rx_input, and receives P decodes for operating the system from the spreading factor generator 101. It receives a spreading factor. In addition, the receiver 110 includes n despreading data buffers 111-11n and a combining processor 120.

Here, the P spreading factors include a phase rotate factor, an antenna configured for system operation, a scrambling code for independent radius cells to be searched through each antenna, and a search radius of individual cells. P spreading factors are generated according to the number of signatures and the number of signatures.

At this time, the P value is equal to or smaller than the n value which is the number of the spreading data buffers 111 to 11n. In addition, the spreading process for detecting the preamble is performed using the received signal and the spreading factor input through the antenna.

The n despreading data buffers 111 to 11n store the despreading data results. The n despreading data buffers 111 to 11n are divided by each cell and then divided by each signature. The spreading buffers 111 ˜ 11n divided by the cell and the signature are combined by the combining processor 120 to report a preamble search result value for k radius antennas for a set cell.

A total of n despreading data buffers 111 to 11n each supporting a minimum radius independently are set in association with each other according to an independent cell radius set for each cell to be searched by the preamble receiver. In other words, each of the despreading data buffers 111 to 111n has a structure as shown in FIG. 1 to support each minimum cell radius.

For example, when one of the despreading data buffers 111 to 11n supports a 5 km cell radius, two of them support a 10 km cell radius and three to a 15 km cell radius. Combined independently for each antenna, the cell radius for each antenna is set to be the same or different.

Accordingly, the number of despreading data buffers 111 to 11n that are set in association to search for one signature varies according to the cell radius, and as a result, the maximum searchable preamble number is a buffer that stores the minimum radius search result. It is equal to the number n of 111 to 11n, and the cell radius setting for the preamble search is determined according to the combination of the number of different cell radii and the number of respective search signatures. The possible combination is limited to the case where it is less than or equal to the number n of buffers required.

As described above, the despreading data buffers 111 through 11n are sequentially divided by cell and signature, and then a preamble result value for the set cell is detected by the combining processor 120 through a combining process. .

A detailed example of combining is as follows.

2 shows an example in which the minimum size of the despreading data buffers 111 to 11n is determined according to a minimum cell radius (eg, 5 km). In addition, if the number n of the total buffer is defined as 16 equal to the number of signatures, the difference between the conventional method and the present invention may be expressed as follows.

In the conventional method, the number of combinations that can be set is [5km radius, 16 signatures], [10km radius, 8 signatures], [15km radius, 5 signatures], [20km radius, 4 signatures], [Cell radius 25km, 3 signatures], [Cell radius 30km, 2 signatures], [Cell radius 35km, 2 signatures], [Cell radius 40km, 2 signatures], [Cell radius 45km, 1 signature], [Cell radius 50km, 1 signature], [cell radius 55km, 1 signature], [cell radius 60km, 1 signature], [cell radius 65km, 1 signature], [cell radius 70km, 1 signature], It can be expressed as [cell radius 75km, one signature], [cell radius 80km, one signature], and in each case, it can be separated into as many antennas as the number of supported signatures.

In the present invention, within the range of 16 buffer numbers [cell radius 5km-16 signatures], [cell radius 5km-14 signatures, cell radius 10km-1 signature], [cell radius 5km-12 signatures, cell radius 10 km-2 signatures], [cell radius 5km-2 signatures, cell radius 10km-7 signatures], [cell radius 5km-11 signatures, cell radius 10km-1 signature, cell radius 15km-1 signature] Etc., the combination is numerous.

That is, in the present invention, one cell radius (5km) or two or more cell radiuses (5km, 10km) (5km, 10km, 15km), etc., and the number of signatures corresponding thereto are maximum 16 to minimum It consists of one, in the case of two or more cell radius, the number of signatures is variable according to the cell radius.

Figure 3 shows an example of a number of combinations by the combining process according to the present invention.

Referring to FIG. 3, if the radius of an A cell is set to 5 km and the number of signatures to be searched is four, four (1, 2, 3, and 4) combined buffers are allocated. The spreading data buffer is responsible for one signature.

If the radius of the B cell is set to 10 km and the number of signatures to be searched is three, two despreading buffers (5, 6) (7, 8) and (9, 10) generate one signature. In this case, a total of six spreading buffers will be allocated.

Next, if the radius of the C cell (antenna) is 15km and the number of signatures is two, the total number of six spreading data buffers (11, 12, 13) (14, 15, 16) can be used to perform the search. have.

In this case, no combining buffer is specified for the A, B, and C cells, but varies depending on the number of signatures and the cell radius.

For example, the combining buffers 1,2,3,4 are allocated when the cell radius is 5 km, but may be used as the combining buffers 5,8,11,12, and the combining combination when the cell radius is 10 km. Combination buffers 5 and 6 are allocated in (bundling), but 11 and 12 may be allocated.

4 and 5 are diagrams comparing the conventional and the cell operating method of the present invention.

4 illustrates an operation method of an existing settable cell. According to the conventional method, the multi-cell search using the same cell radius (20 km) set as the minimum cell (A, B, C, D) radius search unit (for example, 5 km) is shown. That is, conventionally, each antenna (A, B, C, D) is set in a minimum cell radius of 5 km units, and all antennas search for multiple cells using the same cell radius.

5 is a method of operating a configurable cell according to the present invention. As shown in the figure, an example of the present invention in which a search radius (A: 5 km, B: 10 km, C: 15 km) is independently set for each search setting cell (A, B, C) is configured based on FIG. will be. That is, each antenna (A, B, C) is set to different cell changes (5km, 10km, 15km) so that all antennas search for multiple cells through different cell radii.

6 is a flowchart illustrating an operation process of a preamble receiver according to the present invention.

First, the number of antennas set to support multiple cells is determined (S1), and a cell search radius for supporting each cell is checked (S2). By knowing the number of multiple cells and the radius of each cell, the basic minimum operating structure is determined.

Then, the scrambling code for searching the individual cells is checked (S3), and the necessary signatures for searching for each cell are identified (S4).

The internal structure for driving the entire preamble searcher is determined based on the setting contents identified through the above process (S5).

The preamble searcher according to the configuration of the antenna for preamble search of the preamble receiver is driven to report the search result confirmed for each cell (S6).

After the basic driving unit time of the preamble finder elapses, it is checked whether there is a change in the setting for searching, and if there is no change, the search is continued with the same setting contents (S7). If there is a change in the configuration antenna for preamble search of the preamble receiver, the process is repeated again from step S1. In this case, only a partial change is reflected when the changed setting contents are reflected, and in other cases, the existing search process is maintained.

If there is a configuration change for the radius of a specific antenna, the hardware related to that antenna or the entire hardware configuration is initialized and restarted.

As described above, the preamble code receiver and the method of receiving the same according to the present invention have the same hardware resources constituting the preamble receiver, and thus have an effect of enabling a much wider system operation than the conventional scheme.

In addition, since an independent cell search radius can be set for each multiple cell, there is an effect that can be designed and operated for maximum efficiency. In addition, since a specific cell structure can be fully supported within a hardware-configurable maximum radius, the preamble search can be performed without additional system resources, which has a technical and cost advantage over other search methods. By limiting the radius, there is an effect that prevents menstruation of radio waves and prevents unnecessary display buffers from being driven.

Claims (10)

A preamble code receiver of a code division multiple access communication system, N despreading data buffers which receive input of the received signal and P despreading factors and are set in association with each independent cell radius and support a minimum radius; A combining processor in which the number of the n spreading buffers to be combined is determined according to a combination of the number of radii and signatures for one cell radius or k cells having two or more different cell radii; A preamble code receiver of a code division multiple access communication system, characterized in that. The method of claim 1, The spreading factor is determined by an antenna configured for system operation, a scrambling code for cells to be searched through each antenna, and a preamble search radius and the number of signatures of individual cells. receiving set. The method of claim 1, The spreading data buffer is a preamble code receiver of a multiple access communication system, characterized in that divided by each cell and signature. The method of claim 1, And a number of despreading data buffers configured to be linked to search for one signature varies according to a cell radius. The method of claim 1, And a combination of the number of cell radii and the number of search signatures is equal to or smaller than the number of spreading data buffers. The method of claim 1, And the cell radius is determined in units of a minimum cell radius. delete The method of claim 1, The combined n spreading buffers are allocated as many as the minimum cell radius unit, the preamble code receiver of the multiple access communication system. Identifying a number of antennas set to support multiple cells and identifying a cell search radius independently supported for each cell; Checking the scrambling code for each antenna and determining the number of signatures for each antenna; Setting an internal structure including a size of a de- spreading buffer of a preamble receiver according to the number of antennas, an independent cell search radius, a scrambling code, and a number of signatures; And And operating the preamble receiver to report a search result confirmed for each cell according to the setting of the preamble receiver. The method of claim 9, After the basic driving unit time of the preamble receiver has elapsed, check whether there is a setting change for searching, and if there is a change, only some items of the internal structure including the size of the de-extending buffer of the preamble receiver according to the changed item. And resetting the preamble code receiver of the multiple access communication system.

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