KR100934653B1 - How to measure thermal noise power in wireless base station - Google Patents

Abstract

According to an embodiment of the present invention, the wireless communication base station determines whether the thermal noise power is measured at the time of adjusting the overhead channel, and if the thermal noise power is measured, releases the call established between the wireless communication base station and the at least one terminal. The present invention relates to a method for measuring thermal noise power in a wireless communication base station including measuring thermal noise power. In the system, there is an effect of providing a method of measuring thermal noise power at a base station for driving a reverse link supplemental channel (R-SCH).

Description

Method for measuring thermal noise power in a wireless base station {Method for measuring thermal noise power in BTS System}

1 is a basic configuration of a CDMA 2000 1xRTT system to which the present invention can be applied.

2 is a flowchart illustrating a process of measuring thermal noise power according to the present invention;

* Explanation of symbols on the main parts of the drawing

11: Amplifier (Power Amplifier / Low Noise Amplifier)

12: BUDA (BTS sector conversion Up / Down Converter Assembly)

13: controller

14: Channel Card

The present invention relates to a method of measuring thermal noise power in a wireless communication base station, and more particularly, to scheduler driving of a reverse link supplemental channel (R-SCH) in a system that does not have a terminal silence interval designation function. The present invention relates to a method for measuring thermal noise power at a base station.                         

The Code Division Multiple Access 2000 1x (CDMA 2000 1x) system operates in a manner in which all terminals in a cell share a frequency bandwidth of 1.25 MHz, and each terminal supports up to 307.2kbps of data service. It may be provided through a reverse link supplemental channel (R-SCH). However, due to the limitation of the limited bandwidth, not all terminals in a cell can simultaneously receive 307.2kbps data service in the reverse direction, and multiple terminals are simultaneously allocated to the reverse link additional channel having a lower data rate or a high speed such as 307.2kbps can be obtained. Reverse link resources should be managed in such a way that two or three reverse link additional channels are allocated in time divisions.

The capacity of the forward link is most closely related to the base station maximum transmit power, which is already defined for the base station. Therefore, when the base station transmit power is always maintained at the maximum transmit power and efficient resource management of the forward link by using the channel status of the forward link reported from each terminal, it is possible to maximize the forward capacity.

However, unlike the forward link, it is not easy to manage the radio resource in the reverse link because each terminal in the cell uses the radio resource independently. Various methods for efficiently managing reverse link resources have been proposed, and it is known that it is ideal to measure reverse rise (ROT) values at base stations and manage reverse radio resources using the same. The Rise over thermal (ROT) value is a signal obtained by measuring the demodulation input signal power of a receiver and subtracting the system's own thermal noise power by a dB scale from this value, which is a received signal in a wireless section. This is an important value for the total amount of power.

However, unlike 1xEV-DO (1xtreme Evolusion-Data Only) systems, systems such as the CDMA 2000 1xRTT have the ability to suspend backward transmission to terminals in a cell for a specific period of time in order to measure thermal noise power (terminal silence). Since there is no section designation function, it is in principle impossible to obtain Rise Over Thermal (ROT) value through thermal noise power measurement. Therefore, in a system such as 1xtreme Radio Transmission Technology (1xRTT), Rise Over Thermal (ROT) cannot be used to efficiently operate the radio resources of the reverse link, and can be calculated from the reverse data rate of the terminal serviced in the cell. There has been a problem that the radio resources must be managed indirectly using the reverse load.

The present invention has been proposed to solve the above problems, and includes a reverse link additional channel (R) in a CDMA 2000 (Code Division Multiple Access 2000) system that does not have a terminal silence interval designation function such as 1xtreme radio transmission technology (1xRTT). An object of the present invention is to provide a method for measuring thermal noise power at a base station for driving a reverse link supplemental channel (SCH).

The present invention for achieving the above object, the step of determining whether the wireless communication base station is at the time of output adjustment of the overhead channel, the thermal noise power measurement time and the thermal noise power measurement time, the wireless communication base station and at least one terminal Releasing the established call and measuring the thermal noise power.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Rise over thermal (ROT) value required to efficiently manage the reverse link resource can be obtained as in Equation 1.

The heat rise value includes not only all signals received from terminals in a cell, but also signals from terminals distributed in neighboring cells. The reverse capacity is determined by how accurately this value, which changes in real time, is measured at short time intervals.

)을 측정하면 무선으로 수신되는 신호가 없으므로 그 값이 시스템의 열잡음(

) 전력이 되고, 역방향 부하가 존재하는 일반적인 경우에 BUDA에서 측정된 수신 신호 전력(

)은 무선 구간에서의 수신 신호 전력과 시스템의 열잡음 전력을 포함하게 된다. 따라서, 열상승 값 은 무선 구간 만에서의 수신 신호 전력이므로 수학식 2 에 기재된 방법에 의해 구할 수 있다. The thermal rise value may be obtained by measuring baseband received signal power in a BTS sector conversion up / down converter assembly (BUDA). That is, the received signal power (in BUDA) in the absence of reverse load at all

), The signal is received wirelessly, so the value is the system's thermal noise (

) The received signal power measured at BUDA in the general case of power

) Includes the received signal power in the wireless section and the thermal noise power of the system. Therefore, since the thermal rise value is the received signal power only in the wireless section, it can be obtained by the method described in Equation 2.

)을 알아낼 수 있다. 그러면, 그 외의 시간 구간동안 측정된 수신 신호 전력(

)과 특정 시간 구간동안 측정된 열잡음 전력(

)의 차로써 열상승 값을 측정할 수 있게 된다. The 1xtreme Evolusion-Data Only (1xEV-DO) system has a function of stopping backward transmission to all terminals in a cell for a specific time period (terminal silence period) to obtain thermal noise power of the system. For example, if you enable this feature at dawn when the number of calls in service is not high enough that neighboring cell interference is minimal, at least once a day, the system measures the received signal power in BUDA during that time interval,

Can be found. Then, the received signal power measured during the other time interval (

) And thermal noise power measured during a specific time period (

), The thermal rise value can be measured.

Therefore, when the thermal noise power is obtained, the thermal rise value can be obtained using Equation 2, thereby efficiently managing radio resources of the reverse link. However, unlike in the case of 1xEV-DO, a system such as CDMA-2000 (Code Division Multiple Access-2000) 1xRTT (1 extreme Radio Transmission Technic) has a terminal silence section designation function that causes the terminal to stop reverse transmission for a specific time interval. There is no Therefore, in a system such as 1xRTT, it is impossible to periodically measure the thermal noise power of the system.                     

However, in the case of general base station equipment, the BTS Sector Conversion Up / Down Converter Assembly (BUDA) changes the intensity of the transmitted signal little by little over time for various reasons such as heat generation of the board and changes in device characteristics. Since overhead channels such as pilot channel, sync channel, or paging channel must be transmitted constantly, the base transceiver system (BTS) periodically releases all calls to the corresponding terminals of each sector and Carry out adjustments.

In general, the intensity of the thermal noise signal in the receiving section of the base station also changes little by little over time. The cause of the change is not only very similar to the cause of the change in the strength of the overhead signal transmitted in the transmitting section of the base station. The thermal noise signal is very low and changes only slightly relative to the change in the overhead signal, so that thermal noise power can be measured more accurately even if the thermal noise power is measured longer than the transmission intensity adjustment cycle of the overhead signal.

However, the overhead signal power intensity adjustment operation may be performed by releasing the call in sector units, but the thermal noise signal strength measurement operation requires at least all calls in the cell to be relatively accurate. Therefore, each time the strength of the overhead signal is adjusted, the number of calls to be released for this operation increases in order to measure the system thermal noise power of the reception section.

The present invention solves this problem and provides a method for measuring thermal noise power in a system without a terminal silence section designation function.                     

1 is a basic configuration diagram of a CDMA 2000 1xRTT system. As shown in FIG. 1, the CDMA 2000 1xRTT system includes an amplifier 11, a BTS sector conversion up / down converter assembly (BUDA) 12, a controller 13, and a plurality of channel cards 14.

The channel card 14 performs R-SCH (Reverse Link Supplemental Channel) scheduling and requires real-time reverse channel information. The most necessary information for scheduling the reverse channel information is a Rise Over Thermal (ROT) measurement. This Rise Over Thermal (ROT) information is controlled by a controller (for example, RCCA; Radio and Channel Control board Accembly) 13 to instruct the BUDA 12 to measure the heat rise, and according to the command, the BUDA 12. ) Performs the heat rise measurement. That is, the controller 13 functions to report to the channel card 14 the heat rise information collected by the BUDA 12 in real time, and the channel card 14 transmits the heat rise information to the reverse link additional channel scheduling. Will be used.

2 is a flowchart illustrating a process of measuring thermal noise power in a 1xRTT system according to the present invention.

의 값을 1로 초기화한다(21). 여기서

값은 오버헤드 채널 출력 조정 기능(Overhead Channel Calibration)을 수행하였으나 시스템의 열잡음 전력을 측정하지 않은 횟수를 의미한다. As shown in FIG. 2, first

Initialize the value of to 1 (21). here

The value refers to the number of times the overhead channel calibration was performed but the system's thermal noise power was not measured.

의 값이 초기화 되었으면(21), 시스템이 오버헤드 채널 출력 조정 기능을 수행할 시점인지를 판단한다(22). 만약, 오버헤드 채널 출력 조정 기능을 수행할 시점이 아니면 이를 수행할 시점이 될 때까지 기다린다. 그러나, 오버헤드 채널 출력 조정기능을 수행할 시점이라고 판단되면, 현재 상태가 열잡음 전력을 측정하기에 적당한 시점인지를 판단한다(23). 즉, 현재 활성화된 호가 너무 많을 경우에는 모든 호를 해제하고 열잡음 전력을 측정한다는 것이 어려울 것이다. 그렇지만 활성화된 호가 거의 없거나, 활성화된 호가 있더라도 너무 오랫동안 열잡음 전력을 측정하지 못한 경우에는 이를 측정할 필요가 있다.

If the value of is initialized (21), it is determined whether it is time to perform the overhead channel output adjustment function (22). If it is not time to perform overhead channel output adjustment, wait until it is time to do it. However, if it is determined that it is time to perform the overhead channel output adjustment function, it is determined whether the current state is a suitable time to measure the thermal noise power (23). In other words, if there are too many active calls now, it will be difficult to release all calls and measure thermal noise power. However, if there are few active calls, or if there are no active calls and the thermal noise power has not been measured for too long, it is necessary to measure them.

값을 계산하여, 기준치와 비교하는 방법을 사용할 수 있다. 즉, 열잡음 전력 측정하지 않은 횟수(

)에 비해 현재 활성화된 호(

)가 너무 많아

값이 기준치보다 작은 경우에는 열잡음 전력을 측정하기에 적합한 시점이 아니라고 판단할 수 있다. 그러나, 비록 활성화된 호(

)가 있을지라도 열잡음 전력을 측정하지 않은 횟수(

)가 커서

값이 기준치보다 큰 경우에는 열잡음 전력을 측정하기에 적합한 시점이라고 판단한다. As an embodiment of the method for determining whether it is a suitable time to measure the thermal noise power

The value can be calculated and compared with a reference value. That is, the number of times the thermal noise power was not measured (

Compared to currently active calls (

Too many

If the value is smaller than the reference value, it can be determined that it is not a suitable time to measure the thermal noise power. However, although the active call (

), The number of times the thermal noise power was not measured (

) Is large

If the value is larger than the reference value, it is determined that it is a suitable time to measure the thermal noise power.

The reference value is a value that can be arbitrarily designated according to the degree required for thermal noise power measurement. In other words, if the reference value is increased as much as possible, the active call can be maintained, but the thermal noise power cannot be measured frequently. If the reference value is lowered, the thermal noise power can be measured frequently, but the number of calls that need to be released will be increased. .                     

값이 기준치보다 작은 경우라 할지라도 지나치게 오랫동안 열잡음 전력을 측정하지 않으면 문제가 될 수 있으므로, 열잡음 전력을 측정하지 않은 횟수에 상한(

)을 지정하여 실제 열잡음 전력을 측정하지 않은 횟수(

)가 상한을 넘어서는 경우(

)에는 활성화된 호수(

)에도 불구하고 열잡음 전력을 측정하도록 할 수 있다. But,

Even if the value is smaller than the reference value, it may be a problem if the thermal noise power is not measured for too long, so the upper limit on the number of times the thermal noise power is not measured (

) To specify how many times the actual thermal noise power was not measured (

) Exceeds the upper limit (

) Has an active lake (

Can be used to measure thermal noise power.

값을 1 증가시킨 뒤(25) 다음 오버헤드 채널의 출력 조정 기능을 수행할 수 있을 때까지 기다린다. 한편, 이를 측정하기에 적당한 시점이라고 판단된 경우에는 셀 내의 모든 호를 해제한다(26). 그리고, 시스템의 열잡음 전력을 측정한(27) 뒤 오버헤드 채널 출력 조정기능을 수행한다(28). 상기 오버헤드 채널 출력 조정 기능을 수행 하였으면,

값을 다시 1로 초기화 시키고(21), 다음 오버헤드 채널 출력 조정시점이 될때까지 기다린다. As a result of determining whether it is a suitable time to measure the thermal noise power as described above, if it is determined that it is not the proper time, only the overhead channel output adjustment function is performed (24), and the thermal noise power measurement is not performed.

Increase the value by 1 (25) and wait until the next overhead channel's output adjustment function can be performed. On the other hand, if it is determined that it is a suitable time to measure this, all calls in the cell are released (26). Then, the thermal noise power of the system is measured (27) and then the overhead channel output adjustment function is performed (28). If the overhead channel output adjustment function is performed,

Reset the value back to 1 (21) and wait until the next overhead channel output adjustment point.

In the present invention, in order to perform an overhead signal output adjustment operation, all calls in a sector must be released, and this operation is mainly performed at midnight or dawn, when the number of activated calls is smallest.

On the other hand, when it is determined that the time corresponding to the overhead channel output adjustment time and the thermal noise power measurement can be performed, both the measurement of the thermal noise power and the overhead signal power adjustment operation of the base station should be performed. Since all active calls within the cell must be released, all calls within the cell must first be released to measure thermal noise power, and as soon as this is done, the overhead signal source power adjustments for all sectors are performed immediately.

In addition, in the method of the present invention, a method of minimizing the number of calls released by releasing calls and performing transmission power adjustment for each sector is possible. However, in the end, all calls in a cell must be released for thermal noise power measurement, which reduces the time that calls are released at all sectors of the base station at the same time rather than sequentially performing overhead outgoing power adjustments by sector. Is a more preferred method.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention provides a method for measuring thermal noise power in a base station for driving a reverse link supplemental channel (R-SCH) in a CDMA 2000 system that does not have a terminal silence interval designation function such as 1xRTT. It is effective to provide.

Claims (5)

A first step of determining, by the wireless communication base station, whether to measure thermal noise power at an output adjustment time of an overhead channel; And A second step of releasing a call established between the wireless communication base station and at least one terminal and measuring the thermal noise power when the thermal noise power is measured; Method for measuring the thermal noise power in a wireless communication base station comprising a. The method of claim 1, The second step, A third step of adjusting, by the wireless base station, the output of the overhead channel if not at the time of thermal noise power measurement; A method of measuring thermal noise power in a wireless base station. The method according to claim 1 or 2, The first step is,

If it is satisfied that the time to measure the thermal noise power, characterized in that A method of measuring thermal noise power in a wireless base station. (only,

Times the overhead channel output adjustment, but the base station's thermal noise power is not measured,

Is the number of active calls) The method of claim 3, wherein The first step is,

or

When it is satisfied any one of the characterized in that it is determined as the time to measure the thermal noise power A method of measuring thermal noise power in a wireless base station. (only,

: The number of times the overhead channel output is adjusted but the thermal noise power of the base station is not measured.

Is the number of active calls,

:

Upper limit of) The method of claim 4, wherein The reference value is, Characterized in that it is arbitrarily determined to specify the frequency of thermal noise power measurement A method of measuring thermal noise power in a wireless base station.

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