With EDX software, the mobile/remote unit can be a one-way or two-way device, either fixed or mobile. When running area-wide studies, one end of the communication link is the transmitter/sector and the other end is a remote receiver or mobile unit. Depending on the system type, these remote units can be mobile one-way devices like pagers that only receive from the transmitters or mobile two-way devices that also transmit like cellular phones and other two-way radio transceivers. In general, such mobile devices have simple omni-directional antennas that may have fairly arbitrary orientations.

You can also specify one-way and two-way fixed remote units. Such units may be used in wireless local loop applications, utility distribution automation systems, LMDS, or Broadband Wireless Access (BWA) systems. With fixed devices, you specify both co-polarized and cross-polarized directional receive antennas, which are taken into account when calculating and drawing maps of system C/I ratios.

You enter the mobile/remote unit information by selecting RF Systems>Mobile/Remote Unit. A dialog box will appear where you can enter all the parameters for any of the 5 (initially available) remote receivers and/or remote transmitters.

The Mobile tabs across the top of the dialog box are used to select which mobile/remote unit you are editing. For example, by using multiple mobile/remote units and studies, you can easily compare the performance of different types of handsets with different powers. You can also create additional mobile/remote units which can be used for additional area studies. To create additional Mobile tabs, click the “+” icon in the upper right corner of the dialog box. A new Mobile tab will be created where you can modify the attributes of this new mobile/remote unit. To delete a mobile/remote unit, click on the Mobile tab that represents the mobile/remote unit to be removed and then click the “–“ icon in the upper right corner of the dialog box. A Delete Mobile/Remote Unit dialog box appears. 

If you just delete the mobile/remote unit without re-assigning all of the studies that were assigned to it, those studies will not run since that mobile/remote unit is no longer available to use. 

This dialog box prompts you to select an existing mobile/remote unit to assign any studies which may have been assigned to the mobile tab being deleted. Select the desired mobile/remote unit, click OK to continue, and an information box will show how many Area and Route studies (if any) were transferred from the deleted mobile/remote unit to the target mobile/remote unit. 

For Multipoint studies, the mobile/remote units are completely specified in the Customer Premise Equipment (CPE) data, so the information entered here is not relevant.

Antenna Height above location

The receive antenna height information is important for every study type except Multipoint studies. The value you enter for Antenna height above location is the receive antenna radiation center height above ground level (AGL) or above mean sea level (AMSL) depending upon the setting of the Location reference. In the AGL mode, the program will find the elevation of the ground at every receive point throughout the study area. It then adds this receive site ground elevation to the entered receive antenna height above ground to arrive at the receive antenna elevation above mean sea level. The receiver elevation above mean sea level is then used for the path loss calculations. The receive antenna height is also important for shadow map studies.

For special studies, you can choose to enter a value for total height above mean sea level, not the antenna height above ground level. This feature is useful for studies where the receiver is in an aircraft flying at a constant altitude above mean sea level.

Location Reference

When using a building database, these selections give you the choice of having the mobile unit fall inside a building, or be automatically placed on top of the building when running studies, or you can select AMSL which ignores the building database and places the location above mean sea level.

Co‐Polarized Antenna

In the Co-polarized antenna section, you can specify the receiver antenna type, receiver antenna gain, and the name of the antenna pattern data file, if the Use file radio button is selected. These entries are for the co-polarized receive antenna, or in other words, it is oriented to best receive the transmitter signal from a similarly polarized antenna (either vertical or horizontal). This data is only used for C/(I+N) ratio area studies. For such study, it is assumed the receive antenna is oriented in the direction of the strongest co-polarized signal, (or toward the focus transmitter for that study type). The gain and directional antenna pattern data is used to calculate the amount of power received from any other co-polarized signal other than the strongest one, using the directional antenna discrimination in the direction of the other transmitter.

Beneath the antenna Pattern file name entry field, there is an entry for the Cross-polarization antenna rejection. This is the gain difference in the main lobe (maximum gain direction) between the co-polarized antenna and the cross-polarized antenna. The cross-polarized antenna information is only used when C/(I+N) ratio area studies are performed. Assuming the antenna is oriented in the direction of the strongest co-polarized signal (or toward the focus transmitter for that study type), the cross-polarized antenna gain and pattern are used to find the amount of signal that is received from any cross-polarized transmitter where the direction to the cross-polarized transmitter is used with the cross-polarized pattern to make this calculation.

Cable Losses/ Antenna Nearby Obstruction Losses

Specifies losses for cabling used with the mobile/remote unit and additional loss due to obstructions near the antenna, i.e. body loss in the case of a mobile unit worn at belt level.

Use mobile/remote type database

Similar to the transmitters, you can specify the characteristics of your mobile/remote unit in two ways. You can select the receiver type from the Mobile/remote type database equipment list, or you can explicitly enter the values that describe the receiver. The Receiver/remote/mobile equipment list file is named on the RF Equipment list dialog box. If you want to use this equipment list file, click the check box labeled Use mobile/remote type database. The Mobile/remote type drop-down list will then display the mobile/remote types that are available for selection. If you want to enter the values yourself rather than use the receiver type database, the descriptions for each entry are given below.

Transmitter:

RF Out (Max)

In the Transmitter section, this field is used to input the maximum transmitting power of the mobile unit.

RF Out (Min)

Most 2G/3G/4G wireless systems use automatic mobile transmit power control. This entry allows you to set the minimum transmitter power. Only used in CDMA Monte Carlo analysis.

Max EiRP

For studies in which you display the power of the received signal at the base station or transmit sites from the mobile/remote unit, it is essential to specify the transmit power of the mobile/remote unit. The Effective Radiated Power (ERP) is entered here for this purpose. The power units (dBW, mW, etc.) and antenna gain reference (dBi or dBd) are determined from the Map>Units dialog box, and include adjustments for antenna gain, cable losses and nearby antenna obstruction losses.

Min EiRP

Most 2G/3G/4G wireless systems use automatic mobile transmit power control. This entry allows you to set the minimum transmitted ERP value.

APC Headroom

Used in CDMA Monte Carlo analysis to account for some mobile/remote units that might not be capable of achieving the entered Max ERP.

Receiver:

Required service Threshold (no AMOD)

In the Receiver section, the Required service threshold is the minimum acceptable signal strength required by the receiver for “acceptable” performance. “Acceptable” can mean a variety of things in terms of subjective signal quality, so this number can be adjusted to represent systems of varying quality or marginal quality

Required service C/(I+N) ratio (no AMOD)

This is the ratio in dB between the Required service threshold and the sum of the Receiver noise and external interference. For many standard digital systems, this number can be directly interpreted as the C/(I+N) necessary to achieve a given bit error rate (BER).

Receiver Noise/Receiver Noise Figure/Equivalent Receiver Noise Bandwidth

The Receiver noise level is determined using the Equivalent receiver noise bandwidth and the Receiver noise figure (in dB). Appendix F shows the relevant formulas. The Receiver noise level plus any calculated interference is used along with predicted desired signal level to find the received C/(I+N) ratio.

You can enter the Receiver noise level directly if you already know what it is. Alternately, you can enter the Receiver noise figure or the Equivalent receiver noise bandwidth and the Receiver noise level will automatically be calculated.

Receive Filter File Code

Just as a directional antenna can provide discrimination against transmit signals which are not in the direction of the desired transmit signal, the receive filter can provide discrimination against signals that are on a different frequency from the frequency of the desired signal. Again, the receive filter only affects C/(I+N) ratio and BER studies where the desired signal is either: 1) the maximum signal, or 2) the signal from the focus transmitter. If you enter 0, (the default) in the Receive filter file code field, the EDX software assumes there is a rectangular “brick wall” bandpass shape with a width equal to the equivalent noise bandwidth. If you enter a non-zero code number, the EDX software will look in the Library data\equipment subdirectory for a file that describes the filter shape. See Appendix I for more information on receiver filter shape files.

Adjacent Channel Rejection

If the Receiver filter file code is 0, it is assumed that the receiver has a rectangular “brick wall” bandpass shape with a width equal to the equivalent noise bandwidth. Under these conditions, you can set the amount of attenuation on adjacent channels (one bandwidth above and below the desired bandwidth) by entering a value here for adjacent channel rejection. This value will only apply to Area Study calculations.

Nominal RAKE Receiver Gain

In communication systems, such as CDMA, where multipath signal components can be combined advantageously, a RAKE receiver is often employed to improve the SNR. Because a thorough analysis of the benefits provided by a RAKE receiver requires the ray-tracing module and prohibitive calculation, it is modeled in EDX software as an average gain applied to the carrier at the receiver.

Receiver Simulcast Capture Ratio Range

For delay spread studies in a simulcast system, the delay is calculated and displayed only when the power of the strongest received signal and the power of the second strongest received signal are within the capture ratio of each other. The displayed delay spread is then the relative time delay between these two signals in microseconds.