KR19990058813A - Reverse Link Optimization Method for Code Division Multiple Access Networks - Google Patents

Abstract

The reverse link optimization method of a code division multiple access network according to the present invention relates to an optimization test method for a reverse link that can be performed in parallel with the link balancing method.

The present invention analyzes the terminal transmission power data, the terminal transmission gain adjustment data, the reverse frame error rate data, and the noise band bit energy decision point data among the call data collected at the selected test site, and specifies a predetermined range for each data. If not, reduce the forward service range or adjust the noise band bit energy decision point parameter. Through the above process, the appropriate service area of each link is maintained to improve call quality and maintain overall system performance at an optimal state.

Description

Reverse Link Optimization Method for Code Division Multiple Access Networks

The present invention relates to a reverse link optimization method of a code division multiple access network (CDMA network), and in particular, radio parameters and systems of a CDMA system classified into fixed networks and wireless networks. A method of adjusting parameters to configure link balance and reverse link power control to an optimal state.

According to IS-95, an international standardization organization, a typical mobile communication system using Code Division Multiple Access (CDMA) technology includes a mobile terminal (MS) provided with a service and a base station transceiver subsystem (BTS) providing a service. It is configured to include).

The base station is connected to an existing public switched telephone network (PSTN), and a mobile terminal in each cell forms a radio channel with a base station serving a corresponding cell and performs communication. In this case, a channel formed in the direction of the mobile station from the base station is called a forward channel, and a channel formed in the direction of the base station from the mobile station is called a reverse channel.

In the mobile communication system configured as described above, power control for optimizing the quality of the forward and reverse communication links is essential. CDMA systems, by their nature, can service multiple access channels at one frequency. Therefore, minimizing interference between access channels is one of the very important functions in the CDMA system. In order to minimize the interference between channels, the forward coverage, which is the service area by the forward channel, and the reverse coverage, which is the service area by the reverse channel, must be matched. This operation is called maintaining the balance of the link.

1 shows an operation diagram of a link balancing method according to the prior art. As shown, in FIG. 1A, the base station 100 has a circular service area 130 without a load. The service area of the base station 100 is balanced between the forward and reverse service areas without load. The base station 110 also has a circular service area 140 with no load. The base stations 100 and 110 have the same service boundary of 120 under no load.

Referring to (b) of FIG. 1, the base station 110 has a large load, and the base station 100 has a small load. Then, the reverse service area of the base station 110 is reduced to 145. Then, the reverse service boundary of the base station 100 and the base station 110 moves to 125. On the other hand, the forward service boundary is maintained at 120. In order to eliminate such link unbalance, a link balancing process is performed.

In FIG. 1 (c), the base station 110 reduces the forward service area through a link balancing process. Therefore, the reverse service area matches the forward service area, and the reverse service boundary and the forward service boundary coincide.

First, the reverse link power level received at the first and second base stations for the optimization test of the link is measured.

The first based on the reverse link power level measurement at the first and second base stations to maintain equilibrium between locations having equivalent forward link efficiency relative to locations having equivalent reverse link efficiency between the first and second base stations. And adjust the forward link power level at the second base station.

A link balancing method according to the prior art operated as described above is disclosed in US Patent No. 5,548,812, entitled "METHOD AND APPARATUS FOR BALANCING THE FORWARD LINK HANDOFF BOUNDARY TO THE REVERSE LINK HANDOFF BOUNDARY IN A CELLULAR COMMUNICATION SYSTEM."

In the above-described power control method according to the prior art, when adjusting the power level of the forward link, it was adjusted using the power parameters measured in the service area.

However, in practice, the pathloss of the forward and reverse links is not the same for all service areas. Therefore, as a result, it is difficult to meet the link balance regulation values of all regions through standard power parameter adjustment.

In addition, the power transmitted from the terminal may appear differently in the case of a single cell and a multi cell in a handoff area, which is a circuit transfer area between base stations. Therefore, the terminal transmission gain adjustment value may appear different each time it is tested.

As a result, the link balancing method according to the prior art has a problem that its test method and its definition are not suitable for the optimization of the reverse link.

Therefore, in order to solve the problems as described above, the present invention is to optimize the reverse link of the code division multiple access network that can satisfy the link balancing regulation value in all regions to minimize the inter-channel interference within the same frequency in the CDMA system It is an object to provide a method.

1 is an operation diagram of a link balancing method according to the prior art.

2 is a flowchart illustrating a reverse link optimization method according to the present invention.

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

100,110: base station 120,125: boundary line

130,140,145: service area

One preferred embodiment of the present invention devised to achieve the object as described above,

A first step of selecting a test point for reverse link optimization;

A second process of extracting test data by connecting a call channel at each test point;

Terminal transmission power data, terminal transmission gain adjustment data, E _b / N _o Obtaining a mean and a deviation with respect to the decision point data and the reverse frame error rate data;

A fourth step of reducing the forward service area and restarting the test process if the terminal transmit power data is not smaller than a predetermined value;

A fifth step of reducing the forward service area and restarting the test process if the terminal transmission gain adjustment data is not smaller than a predetermined value;

A sixth process of restarting the reverse process; And

E _b / N _o If the decision point data is not within the specified range E _b / N _o And a seventh step of adjusting the decision point parameters to place them within the specified range and to restart the test process.

In the present invention, the reverse link optimization method includes: a first step of selecting a test base station configured with multiple cells;

Adding a 90% load to the surrounding tier base station using OCNS;

A third step of configuring a non-service state in all neighboring first base stations; And

Preferably, the test environment further includes a test environment configuration process including a fourth step of adding 80% load to the base station under test using an actual call.

The reverse link optimization method is preferably performed in parallel with the link balance test,

The reverse link optimization method includes six points in the handoff region and a terminal E _c / I _o It is desirable to select 6 test points at between -8 dB and -10 dB.

In the reverse link optimization method, it is preferable to reduce the forward service area by adjusting the attenuation value of the base station transmitter.

The reverse link optimization method includes adjusting power control system parameters Pwrctl_min, Pwrctl_max, and Pwrctl_norminal. E _b / N _o It is desirable to adjust the decision point parameters,

Preferably, the designated value of the terminal transmission power data is +23 dBm.

Preferably, the designated value of the terminal transmission gain adjustment data is 0 dB.

It is preferable that the designated value of the reverse frame error rate is 1%.

The present invention proposes a link balancing method for matching a service area on a forward link with a service area on a reverse link in a CDMA system using a single frequency to service multiple access channels. Hereinafter, a test example for testing a reverse link using the present invention will be described.

First, a test base station consisting of multiple cells is selected.

A 90% loading is added to an adjacent tier base station using an orthogonal code noise simulator (OCNS).

All neighboring first base stations are configured in a non-service state.

A 90% load is added to the base station under test using a real call.

6 points in the handoff area and the current-to-signal ratio of the terminal E _c / I _o Select 6 points with) within -8 dB to -10 dB as the test points.

2 is a flowchart illustrating a reverse link optimization method according to the present invention. Referring to the drawings, the reverse link optimization method according to the present invention will be described.

Start the reverse link optimization test procedure for each point (210). First, a call channel is connected to each test point at a predetermined test point. The tester is at rest at this time. Once the call channel is connected, perform a call for approximately three minutes to extract test data for link testing. Test data for the forward link is extracted at the test terminal and test data for the reverse link is extracted at the base station (or base station controller). Among the extracted data, the terminal transmit power (Mobile Tx Power) data, noise band bit energy ( E _b / N _o ) The average and the deviation of the set point data, the mobile Tx Gain Adjust data, and the Reverse Frame Error Rate (RFER) data are calculated.

In the extracted test data, it is determined whether the terminal transmission power data is smaller than +23 dBm (220). If it is not smaller, the forward service area is reduced, and the reverse link optimization test procedure for each point is restarted (230). To reduce it, increase the base station (or base station controller) transmitter attenuation.

If the terminal transmit power data is less than +23 dBm, it is determined whether the terminal transmit gain adjustment data is less than 0 dB (240), and if it is not small, the forward service area is reduced. The reverse point reverse link optimization test procedure is restarted (230).

If the terminal transmission gain adjustment data is less than 0 dB, it is determined whether the reverse frame error rate data is less than 1% (250). .

If the reverse frame error rate data is less than 1%, E _b / N _o It is determined whether the set point data is between the specified minimum and maximum values (260).

if E _b / N _o If the decision point data is close to the maximum value, it is interpreted that the terminal is located outside the reverse link boundary due to the increase of the reverse frame error rate. Contrary E _b / N _o Even if the decision point data is close to the minimum value, it can be interpreted that the forward and reverse links are not balanced. therefore, E _b / N _o If the decision point data is not within the specified value E _b / N _o The decision point parameter is adjusted to be within the specified value, and then the point-by-point reverse link optimization test procedure is restarted (230). At this time, by adjusting the power control system parameters Pwrctl_min, Pwrctl_max, Pwrctl_norminal E _b / N _o Adjust the decision point parameter (270).

If the judgment on all the data is normal, the reverse link optimization test procedure is terminated.

According to the present invention operating as described above, the battery usage time of the terminal can be increased by appropriately using the transmission power of the terminal, and the resource capacity of the system can be maximized by reducing mutual interference between terminals. Maintaining the right coverage area can also improve call quality and optimize overall system performance.

Claims (9)

A first step of selecting a test point for reverse link optimization; A second process of extracting test data by connecting a call channel at each test point; Terminal transmission power data, terminal transmission gain adjustment data, E _b / N _o Obtaining a mean and a deviation with respect to the decision point data and the reverse frame error rate data; A fourth step of reducing the forward service area and restarting the test process if the terminal transmit power data is not smaller than a predetermined value; A fifth step of reducing the forward service area and restarting the test process if the terminal transmission gain adjustment data is not smaller than a predetermined value; A sixth step of reducing the forward service area and restarting the test process if the reverse frame error rate is not smaller than a predetermined value; And E _b / N _o If the decision point data is not within the specified range E _b / N _o And a seventh step of adjusting the decision point parameter to be within a specified range and restarting the test procedure. The method of claim 1, wherein the reverse link optimization method comprises: Selecting a test base station configured with multiple cells; Adding a 90% load to the surrounding tier base station using OCNS; A third step of configuring a non-service state in all neighboring first base stations; And And a fourth step of adding a load of 80% using the actual call to the base station under test, further comprising a test environment configuration process. 2. The method of claim 1, wherein the reverse link optimization method is performed in parallel with a link balance test. The method of claim 1, wherein the reverse link optimization method comprises: six points of a handoff region, and a terminal; E _c / I _o A method of reverse link optimization in a code division multiple access network, wherein 6 points of which are -8 dB to -10 dB are selected as test points. 2. The method of claim 1, wherein the reverse link optimization method reduces the forward service area by adjusting attenuation values of base station transmitters. The method of claim 1, wherein the reverse link optimization method comprises adjusting power control system parameters Pwrctl_min, Pwrctl_max, and Pwrctl_norminal. E _b / N _o A method of reverse link optimization in a code division multiple access network, adjusting decision point parameters. 2. The method of claim 1, wherein the specified value of the terminal transmit power data is +23 dBm. The reverse link optimization method according to claim 1, wherein the specified value of the terminal transmission gain adjustment data is 0 dB. 2. The method of claim 1, wherein the specified value of the reverse frame error rate is 1%.