KR100810972B1 - A method of quantifying the quality of service in a cdma cellular telephone system - Google Patents

Abstract

The process of determining all locations of a service area, subject to constraints that cause interference, assigns an average service level to each of these locations, and adds the service levels at all these locations, thereby providing service levels at all these locations. The sum is divided by the total service level for the service area to generate an interference value.

Description

A METHOD OF QUANTIFYING THE QUALITY OF SERVICE IN A CDMA CELLULAR TELEPHONE SYSTEM}

1 is a CDMA cellular telephone system employing the method of the present invention.

2 is a flow chart illustrating a process in accordance with the present invention.

3 is a flowchart illustrating a specific example of a process according to the present invention.

4 is a diagram showing a process in which data to be used in the present invention is accumulated.

FIELD OF THE INVENTION The present invention relates to cellular telephone systems and, more particularly, to a method of quantifying the performance of a CDMA cellular telephone system.

Currently available commercial mobile communication systems typically include a plurality of fixed base stations (cells) that transmit and receive signals to and from mobile units within their communication area. Each base station is assigned a plurality of channels capable of communicating with an autonomous body. Mobile units within range of the base station communicate with the outside world through the base station using this channel. Typically, the channel used for a base station is chosen so that signals on any channel do not interfere with signals on other channels used by the base station.

In order for a mobile unit to transmit and receive telephony while traveling over a large area, each cell is typically physically located such that its coverage area is adjacent and overlaps with the coverage area of a plurality of other cells. When a mobile unit moves from an area covered by one base station to an area covered by another base station, communication with that mobile unit is transmitted from one base station to another in the area covered by coverage from different cells (hand off). .

Cellular telephony communication between the mobile unit and the cell should be made without possible interference. How it is implemented depends on the characteristics of the particular cellular system.

In the most popular US mobile telephone systems (AMPS), channels are defined as frequencies. Frequency bands providing approximately 400 different adjacent FM frequency channels are assigned to each cellular system operator. In a typical AMPS system, each channel uses a fixed FM frequency band for downlink transmission from the base station to the mobile unit and another fixed FM frequency band for uplink transmission from the mobile unit to the cell. Typically, the frequencies allocated for downlink transmissions for the entire AMPS cellular system are immediately adjacent to each other and are widely separated from the frequencies assigned for uplink transmissions immediately adjacent to each other.

Since channels in an AMPS system are defined by frequency, interference with any particular transmission is essentially due to transmissions on the same or immediately adjacent channel. To reduce this interference, the operator assigns channels that are separated from each other in frequency to any single base station to sufficiently eliminate interference between these channels. For example, an operator may assign a set of channels to a base station with frequencies that are separated from the next by many (eg, 21) channels carrying intermediate frequencies.

In addition, in an AMPS system that moves from an area covered by one base station to an area covered by another base station, the mobile unit is moved from one base station in the area where the cell coverage overlaps to another, so that the cell coverage overlaps with the base station. Interference should be eliminated. To do this, the channel assigned to the adjacent cell is carefully chosen to remove the same frequency. Sometimes, this assigns a channel to a center cell that is widely separated in frequency in the manner described above, and then uses the pattern to increase each channel assignment by the number of each sequential cell surrounding that center cell. This is done by assigning a channel to the surrounding cell. As a result, a cell having a center cell surrounded by a plurality of overlapping cells transmitting on different frequencies may be viewed as a honeycomb pattern. Such a honeycomb pattern extends outwards throughout the system with each cell surrounding a center cell functioning as a center cell surrounded by its overlapping cell, resulting in a pattern referred to as a reuse pattern. In this pattern, the interference on the same channel occurs in a cell slightly away from the cell carrying useful information.

In most cellular systems, especially in urban systems carrying heavy traffic, the location in which the cell is placed may be two or three separate transceiver stations, each of which may include a channel having a frequency assignment of the channels described above. (Referred to as sectors). Antennas in each sector are typically arranged to provide 120 or 180 degrees of coverage. The terms cell, sector and base station are typically used interchangeably herein, unless the content indicates otherwise. If the AMPS system includes a significant number of partition cells, all six cells arranged in a honeycomb pattern surrounding the center cell can be allocated differently, and in theory can be non-interfering channels. However, outside of the initial center cell and the cells directly surrounding it, the frequency reuse pattern requires the channel to be copied in a much closer range than in an unpartitioned system.

In a common type of another mobile system called time division multiple access (TDMA), frequencies are assigned to groups in the entire system, just as frequencies are allocated in AMPS systems. However, within any frequency, each base station transmits and receives in bursts for some different intervals or time slots. Within the frequency band these time intervals effectively organize the individual channels. By using this interval and by ensuring that the frequency groups assigned to any individual base station are different from each other and the frequencies assigned to the base stations surrounding each individual base station, the time division process allows for substantially better use of the frequency spectrum. Channel reuse patterns are established.

A new type of mobile system called code division multiple access (CDMA) uses encoded digital signals to transmit data. All base stations and mobile units in a CDMA system transmit encoded digital signals using the same "spread spectrum" frequency band of 1.25 megacycles, although other bandwidths are currently proposed. The information bits of each transmission are extended using coding information called pseudo noise (PN) codes. Each sector throughout one system encodes the transmitted information using the same PN code. Each sector then identifies itself using a time offset (generally referred to as a pseudo noise (PN) offset) from the repeating initial time in its extended transmission. Thus, one sector can start encoding transmission at an initial time, the second sector can start encoding transmission at an offset of one unit from that initial time, and the third sector can start encoding transmission at an offset of two units. In this way, a total of 512 offset units can be achieved. Each transmission in the sector is located on that which is effectively an individual channel by encoding the extended transmission with one of a plurality of Walsh codes. Walsh codes are masks used to encode and decode transmissions that remove transmissions sent using other Walsh codes. The transmission on a particular channel is decoded by applying a mask containing the Walsh code and the PN code to the reception pattern of information bits starting at the PN offset specified for the particular channel.

The transmitting CDMA system offers many advantages. One of these advantages is that the mobile unit can receive the same information from multiple different cells or sectors at the same instant. Since all transmissions occur in the same frequency band, the mobile unit actually receives all the information available within that range. However, it only decodes the information on the channel it is directed to. A CDMA mobile unit uses a receiver that can apply a plurality of decoding masks to the entire spectrum of information it receives at the same instant. By recognizing the Walsh code and the PN offset defining the channel to be received, the mobile unit can decode the information from one message sent by a plurality of different base stations, while combining the information to produce a single output message. Thus, a signal from one sector can be faded while the same message can be received at an appropriate strength from another sector. This allows CDMA to have a fairly good transfer.

In AMPS and TDMA systems, inter-channel interference can be reduced by validating the frequency reuse scheme in the manner described above. In theory, this type of cell placement and channel allocation ensures that the channel reuse pattern is repeated at significant distances so that there is no interference between mobile units on the same and adjacent channels.

Unfortunately, interference due to various reasons occurs in AMPS and TDMA systems even though the frequency reuse scheme is well chosen. Antenna pattern, power level, scattering, and wave diffraction vary from cell to cell. Buildings, various other structures, hills, mountains, forests, and other physical objects cause signal strength to vary over the area covered by the cell. As a result, the boundary at which the signal strength of the channel falls below a level sufficient to communicate with the mobile unit can vary widely within and between cells. For this reason, cells that are actually adjacent to one another do not typically form the exact geometric boundary proposed above. Because the cell boundaries overlap to provide full coverage of the area and allow handoff, and because the boundaries of the cells are inaccurately defined, signals may be generated by cells at a theoretically sufficient distance to eliminate interference It will sometimes interfere with each other. This is particularly true when using partitioned cell patterns because the cells are much closer to each other than in simple cell patterns.

In an AMPS system, a first signal on a channel from a remote cell is a powerful second that carries a mobile transmission on the same channel in the coverage area of the cell when the drop in first signal strength from the second signal is below a threshold level (typically 18 decibels). Interfere with the signal. At a frequency close to the frequency of the channel carrying the mobile transmission, the signal from another cell on the channel interferes when the drop in the interfering signal strength from its providing signal is below a second threshold level (typically 6 decibels).

Historically, to determine if there is interference in an AMPS system, mobile system operators have relied on customer complaints. When a customer registers enough inconvenience about communication at a particular point in the system, the operator performs a relatively expensive field test on the suspicious portion of the system to measure the signal strengths received from the different cells. During the test, the part of the system on which the test is performed is essentially disabled. As expensive and inconvenient, these tests are usually limited to questionable areas. Since these tests are limited to determining the interference at points where the system operator expects interference, the efficiency is very questionable. An important problem with this process is that it only tests where the wide range of interference is reported, making it impossible to fully understand the interference that actually exists in the system. The process does not take into account all possible signals that can propagate in this affected area so that it does not consider at all the effect that changes in channel assignments may have in other areas of the system. Occasionally (possibly as possible), the method of healing this interference propagates interference to other parts of the system that are only found when confirmed by field tests of newly isolated interference areas due to many complaints. Also, the method of eliminating this interference is very slow and laborious. Testing a medium system to eliminate interference may require 400 man hours. The process is quite costly without being able to reliably eliminate interference. Because of the nature seen for cellular telephones, interfering system changes, such as increased traffic, occur at a constant rate of acceleration.

Recently, the quality of service provided by an AMPS or TDMA system has been determined to be a fixed and verifiable amount such that, with the expectation that changes can have the desired result in substantially improving the quality of service provided by the system. Processes have been devised that allow changes to improve quality of service. The process utilizes the data collected while driving the service area where the transmitted and received signal strengths are obtained at respective locations throughout the service area. These values provide actual data from which all locations where interference can occur can be determined. Knowing where interference may occur may allow an operator to quantify the amount of service so that a value is assigned to a particular service area where a change in the system may be required. This process is assigned to the assignee of the present invention, and the name of the invention is a method of improving the operation of a cellular telephone system, and US patent application Ser. No. 08 / 887,101 filed July 2, 1997 by E. Jensen et al. Is disclosed.

In theory, unlike other types of systems, CDMA transmissions should be interference-free throughout the system because they are decoded into digital information using a mask that is expected to eliminate the interfering signal. However, in a CDMA system all transmissions are carried by bits transmitted on the same frequency spectrum. For this reason, information received by a mobile unit or cell is effectively interfering if the information is not directed to a particular receiver. In other words, because the receiver receives all transmissions that occurred on any transmitter within range, the untransformed transmission constitutes interference in the CDMA system. Typically, before decoding, the desired transmission should have an intensity of at least -14 dB when compared to the total strength of all received transmissions. When the strength of the desired transmission falls below this point, the digital details of the message can be retrieved from the spectrum.

The encoding of the signal provides a sufficient encoding gain since each information bit is extended by a plurality of bits at each coding level. A decoding transmission approximately 7 ms larger than the current interference after decoding is sufficient to provide a signal of sufficient quality.

Because of the different meanings of interference in other types of cellular systems, the above-mentioned method of quantifying the quality of AMPS or TDMA is not useful when applied to CDMA systems. As a result, interference in a CDMA system is typically eliminated by increasing the number of sectors as transmissions in one sector increase more than a certain maximum number of times. However, this criterion has been determined to be difficult to handle whether any particular sector can handle additional transmissions. Adding sectors to the system is an expensive way to handle interference.

As a result, it is desirable to provide a new process that can improve the system by taking several steps so that the quality of the CDMA cellular system is quantified.

The present invention determines all allocations of service areas affected by constraints that cause interference, assigns an average service level to each of these locations, adds service levels at all of the locations, and services at all of the locations. This is realized by a computer running process that generates an interference value by dividing the sum of the levels by the total service level for the service area.

Referring now to FIG. 1, a CDMA cellular telephone system 10 is shown that includes a plurality of individual base stations 12 arranged to provide coverage of a service area. Each base station in FIG. 1 is shown with an external boundary 13 indicating the limit of the effective communication range. The borders 13 of other adjacent base stations typically overlap.

Each base station 12 includes at least one cell for communicating with a mobile unit 15 operating within its service area. In many cases, a base station includes two or three sectors each with communication equipment communicating with multiple mobile units in an area defined in part by an antenna pattern angle of 180 degrees or 120 degrees from the base station. All transmissions between base stations and mobile units in a CDMA system are digitally encoded and carried on the same spread spectrum frequency band of 1.25 MHz. The digital information bits of each transmission are determined using the coding information of the various information. One such level is called a PN code. Each sector through the system encodes the transmission information using the same PN code. Each sector then identifies itself by using an extended transmission offset (generally referred to as a pseudo noise (PN) offset) at several repeated initial points, typically established through communication with a general purpose location system. Thus, one sector starts encoding transmission at its initial time, the second sector starts encoding transmission at one unit offset from its initial time, and the third sector starts encoding transmission at an offset of two units. This leads to a total of 512 offset units. Each transmission in the sector is located on being effectively a separate channel by further encoding the extended transmission into one of a plurality of Walsh codes. The transmission on a particular channel is decoded by applying a mask containing the Walsh code and the PN code to the reception pattern of information bits starting at the PN offset specified for the particular channel.

The CDMA system of transmission offers many advantages. One of these advantages is that the mobile unit can receive the same message from a plurality of different cells or sectors at the same instant. Since all transmissions occur on the same frequency band, the mobile unit actually receives all the information available within that range. However, it only decodes the information on the channel directed to the mobile unit. The CDMA mobile unit uses a receiver that can apply a plurality of decoding masks to the entire spectrum of received information at the same instant. By knowing which channel the mobile unit wants to receive, the mobile unit can generate a single output message by decoding the information from a single message sent by a plurality of different sectors and combining the information at the same time. Thus, a message provided in one sector can be faded while the same message can be received at an appropriate intensity from another sector. This may offer the possibility of a CDMA system transmitting very well.

Despite these advantages, CDMA systems have problems. One of these problems is caused by the fact that all transmissions occur on the same frequency spectrum. Since all transmissions occur on the same frequency spectrum band, the mobile unit can actually receive all transmissions available within that range. Transmissions that are not directed to a particular receiver tend to hide the desired transmission. When a transmission level not directed to the particular receiver reaches a level above 14 dB above a predetermined signal level before decoding, it becomes difficult to decode the desired transmission.

In addition, when decoding information directed to the mobile unit using a PN code mask and Walsh code mask at a specific PN offset, these masks cannot completely reject all unwanted incoming communication. The transmission path changes as a length and a sufficient delay must be provided to detect the signal directed to the mobile unit. An important factor when providing good transmission quality in a CDMA system is to maintain the desired transmission strength at a level of 7 kHz greater than all interference levels received after decoding.

Indeed, the CDMA system includes a feature that automatically increases or decreases the power level in the sector and the mobile unit for clear transmission. The mobile unit measures the strength of the signal by measuring the rate at which errors occur in the received signal (frame error rate). When the error becomes higher than the above-described limit, the mobile unit transmits a signal to the sector to increase its transmission strength. The sector does this but gradually decreases the signal strength from a high level until it changes the sector again to increase the transmission strength. Thus, when the signal drops to a level that is too high to indicate an intensity of less than 7 above the interference level, the sector automatically increases the power of the transmitted signal to raise the received signal level for interference. Its signal quality is improved.

In a similar manner, the sector measures the strength of the signal received at the mobile unit by monitoring the frame error rate and indicates to the mobile unit whether to increase or decrease its transmission strength. When a mobile unit contacts a plurality of sectors, the mobile unit receives signals from all sectors indicating whether to increase or decrease its transmission strength. The mobile unit decreases the strength of the signal in response to an arbitrary signal because a single strong signal provides the mobile unit with no interference. In so doing, the mobile unit attempts to transmit at a minimum signal strength sufficient to provide high sound quality.

Because of this power control, the signal strength from the desired transmission for the total received signal should theoretically be the same throughout the service area. In fact, as long as you have the ability to control power, you have the ability to add users and channels without compromising the quality of service. As a result, many sectors already serving many users can add channels and users without interference in transmission with the mobile unit. However, the ability to adjust the power level may function when either the sector or the mobile unit has reached any of a variety of maximum power levels, making it unable to respond to that power control signal. In such a case, the transmission of the system is subject to interference, resulting in poor quality of service.

More particularly, each sector is assigned a maximum signal strength level for all transmissions and cannot increase its signal strength when transmitting at that maximum level. In addition, each sector is limited to the maximum signal strength for any individual signal sent to the mobile unit. In the same way, each mobile unit is limited to the amount of power it can transmit. As a result, whenever any of these power maximums are reached, the system cannot adjust the power to eliminate interference.

It would be very useful to be able to quantitatively evaluate the quality of services experienced in the CDMA service domain. For example, in an AMPS system, all actual signal strengths to be transmitted between a plurality of cells and mobile units at a plurality of locations throughout the entire mobile communication system are measured, and data representing the actual strengths of all the signals is physically transmitted. Identify a cell transmitting a signal capable of associating a location with each location and serving each location, and compare the frequency used by any cell serving the location with the frequency used by another cell to serve the location. Identify a cell transmission signal that may interfere with the transmitted signal, determine whether the frequency used for any cell serving a location interferes with the frequency used for another location across the entire mobile communication system, Interference on the system can be quantified.

However, unlike AMPS and TDMA systems, all signals received at a particular location on the same frequency measure their strengths, compare their strengths to determine if interference can occur at that location, and add locations that indicate interference. Determining the quality of service is not simple.

All transmissions received at any location in a CDMA system are on the same frequency. There may be multiple transmissions received at the same time at any location. The most desired transmission is self-tuning for the unwanted transmissions so that useful messages can be received. Determining where the interference problem is is not a simple method.

The process is described in the flowchart of FIG. First, the process identifies all locations (measurement location 17 is shown in FIG. 1) where service throughout the system is expected to drop. This is done by determining whether it is one of three problems that attenuation occurs in a CDMA system. When the sector transmitter amplifier reaches maximum power, when the sector reaches the maximum sector power allocated to the individual transmission, or when the maximum mobile power is reached, the location is where the degraded service appears. .

To make this determination, data relating to signal strength at locations throughout the service area is used. This may be the same data collected for use in an AMPS or TDMA system used in the same area. In addition, the data may be accumulated data to specifically quantify the quality of the CDMA service in the service area. In any case, the specific data used is data indicative of the transmission signal strength of the transmission in the sector, the reception signal strength of the transmission in the location and the reception location. In general, each of these values is accompanied by timing data useful for relating the signal to sectors and positions.

This data is collected as shown in FIG. 4 by a mobile unit having means (typically a computer) for logging a received signal over time and location, traveling with an scanning receiver one area. In an AMPS system, the data must be collected while a large portion of the service area intersects and each sector can transmit on a different frequency than the frequency used for the other sector. This allows the transmission sector to be identified and its transmission strength determined.

In a CDMA system, the data may be collected using a spread spectrum receiver (called a PN scanning receiver) capable of decoding the PN offset transmitted by one sector. The spread spectrum receiver measures the strength of a pilot signal continuously transmitted by a base station on a control channel (pilot channel) defined by a particular Walsh code. This pilot signal can determine the sector to which the mobile unit should be contacted. When detecting a pilot signal on the pilot channel, the time the transmission arrives is compared to the system initial time provided on the other " synchronized " control channel to determine the PN offset of the transmission. The transmission sector using the PN offset can be identified and the transmission strength received at the location of any sector can be determined. All of this data is accumulated and stored by the computer associated with the spread spectrum that collects the data.

When the data is accumulated, it can be manipulated by computer software designed according to the invention of the method described below. This description can be better understood with reference to FIGS. 2 and 3, which illustrate the flow of operation.
Along with the strength of the transmitted signal and the available received signal, the path loss for each transmission from any sector to any location can be determined.

When calculating the quality of service in a CDMA system, all measured transmit strengths (comprising pilot signals, other control signals, and signals directed for the user) reaching each location are summed to provide the total received strength received at that location. Can lose. The sum of all signal strengths received at a location constitutes an interference level at that location (referred to as N _O ). The strength of the pilot signal Eb received at this location to provide a quality signal can be determined as a decoded signal at a level only 7 dB above the total interference level No. Of course, that particular level may vary depending on the equipment actually used for the operation.

The minimum signal strength required at the location may be added to the loss between the location and the sector to determine the transmitted signal strength required for the channel at the sector transmitter. If this power is not available, the sector reaches its maximum for the channel, and that location is the location where there is an interference problem for that sector.

During the operation of calculating transmission strength from each sector, the sum of the transmission strengths from each sector for all locations can be accumulated and added to determine for each sector whether the total sector power is maximum. If the total sector power is maximum, then the sector may not provide adequate signal strength for a plurality of mobile units whose interference is problematic for the system.

Finally, the sum of all received (interfering) transmissions in the sector is determined to determine whether the mobile transmitter provides more than the maximum power to provide a quality signal to the sector at one location. From this sum, a value 7 dB greater than this sum is calculated to determine the minimum received signal strength needed in the sector for the quality signal. This (minimum received signal strength + path loss for the location) provides a value representing the signal strength available at the mobile unit. If this value is greater than the maximum power available at the mobile unit, then the location has an interference problem for that sector. By calculating this necessary transmission value for each sector expected to communicate with the location, it is possible to determine whether there is an interference problem for each sector of the system where communication can be expected.

Once all locations representing degraded services have been identified, the number of such locations is added for the service area. This sum is multiplied by the average traffic level determined from the traffic expected for the service area. For example, if a service area serves 10 mobile customers and there are a total of 100 locations in the service area, each location may be expected to have an average traffic level of 1/10 of the customer. This average traffic level multiplied by the number of problem locations provides a value for the problem locations in the service area.

In other embodiments, the various locations throughout the system are assigned traffic levels according to an estimate of the actual and overall traffic volume that may or may be experienced. In the service area, the traffic levels for all problem areas are summed to reach an overall value.

The total value for the location of the problem in the service area is divided by the total number of users expected for the service area to determine a score for the service area that indicates the problem as a percentage of the area provided that the number of expected users is provided. This score may be compared with the scores for other service areas to determine whether a particular service area is an area that needs to be modified to improve the system. It should be noted that the particular service area may be a service area for the entire system, a portion of the system and a single sector.

It should be noted that the use of data actually obtained by running the system eliminates the need to evaluate based on environmental models that are not necessary to represent any particular system. In addition, the method of the present invention may utilize data useful for many different usage levels and change the usage level while determining the quality of service for the particular service area. This allows planning for service areas without the need to recollect data.

Although the present invention will be described based on the preferred embodiments, those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the invention.

Claims (5)

A method of quantifying a quality of service in a CDMA cellular telephone system 10, Identifying all locations of the service area having a performance degradation operation; Assigning a value to each location 17 where degradation performance can be expected, the value representing an average level of service at that location; Adding service average levels of all locations of the service area with a performance degradation operation; Determining a service level of the entire service area; Dividing the sum of all service average levels of locations of the service area by the service level of the entire service area, with a performance degradation operation, to obtain a value indicating a quality of service for the service area; Identifying all locations of the service area, having a performance degradation operation, Determining total interference for each location from data definition signals received at each location in the service area; Determining a received signal level required to provide quality transmission at each location 17; Determining a path loss between each location and each base station 12; From each base station 12, the transmission signal level required at each location 17 where signals are expected, the received signal level required to provide quality transmission at that location, and the location 17 and each base station 12 Determining based on path loss of the liver; Comparing the maximum channel transmit power with a level of the required transmit signal. A method of quantifying a quality of service in a CDMA cellular telephone system 10, Identifying all locations of the service area having a performance degradation operation; Assigning a value to each location 17 where degradation performance can be expected, the value representing an average level of service at that location; Adding service average levels of all locations of the service area, for which a degraded operation may be expected; Determining a service level of the entire service area; Dividing the sum of all service average levels of locations of the service area by the service level of the entire service area to obtain a value representing the quality of service for the service area, having a performance degradation operation; Identifying all locations of the service area, having a performance degradation operation, From each base station 12, the transmission signal level required at each location 17 where signals are expected, is the received signal level required to provide quality transmission at that location, and between the location 17 and each base station 12. Based on the path loss, determining; Adding up the levels of all transmitted signals from each base station; And comparing the sum of the levels of all transmission signals from each base station with the maximum transmission power of the base station. A method of quantifying a quality of service in a CDMA cellular telephone system 10, Identifying all locations of the service area having a performance degradation operation; Assigning a value to each location where degradation performance can be expected, the value indicating an average level of service at that location; Adding service average levels of all locations of the service area with a performance degradation operation; Determining a service level of the entire service area; Dividing the sum of all service average levels of locations of the service area by the service level of the entire service area to obtain a value representing the quality of service for the service area, having a performance degradation operation; Identifying all locations of the service area, having a performance degradation operation, Determining total interference for each base station from data definition signals received at each base station (12) in the service area; Determining a received signal level required to provide quality transmission at each base station; Determining a path loss between each location 17 and each base station 12; From each location 17, the transmission signal level required for each base station 12 for which signals are expected is based on the received signal level required to provide quality transmission at the base station, and the location and path loss between each base station. Determining; And comparing the channel transmit power with the level of the required transmit signal. The method according to any one of claims 1 to 3, Assigning a traffic level to each location (17) containing a degraded service; Quantifying the quality of service in a CDMA cellular telephone system further comprising combining the traffic levels for all locations that include a degraded service to obtain a total value for locations that include a degraded service. How to. The method of claim 4, wherein Dividing the total value by the total number of users expected for the service area to determine a score for the service area, wherein the score indicates a percentage of problems for a given area. Quantifying the quality of service in a CDMA cellular telephone system.

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