– by Brian Jones, EDX customer success.

Introduction

Uplink or Talk-In studies can sometimes return a result for a given location (mobile/remote or CPE) related to an unexpected or counter-intuitive base station sector. For example, if a site has a stronger downlink signal from sector A, but a stronger uplink signal to sector B, a typical uplink study such as Received power at best base from remote returns the uplink signal power to sector A. If the network technology in question assigns traffic on the basis of the downlink signal power, then this is the correct behavior. But in the case of many land-mobile systems or other networks with voting receivers, this is an undesirable result. 

Server Selection Criteria

Most SignalPro studies (area, route, and multipoint) base the server selection at each location on the option configured in the Studies > Server Selection Criteria dialog, similar to the following:

Open

Server Selection Criteria Dialog

Voting Receiver Studies

If the network technology in question can utilize the uplink signal at any sector, regardless of downlink power, then they’re often called voting receivers. This is because the system votes on which sector receiver has the best signal level and uses the best uplink sector to receive incoming signals. Simulcast systems and/or systems with receive-only sites are common examples of voting receiver systems. The following studies are appropriate for voting receiver systems:

 Received power at best voting receiver from remote

This study finds the strongest uplink sector and reports its uplink power, regardless of downlink signal strength. This is the correct received power study to use for this type of network. 

Uplink percent lognormal reliability using voting receivers

This study finds the single strongest uplink server and then applies lognormal fading. It then reports the percent chance of the uplink signal’s value exceeding the required service threshold for that sector. This is correct for a traditional voting receiver network. 

Uplink percent lognormal reliability with Macro Diversity voting

This study finds the uplink signal strength values for up to six sectors. It reports the percent chance of at least one of the uplink signals exceeding the required service threshold using lognormal fading. This study type accounts for newer macro-diversity voting systems with the uplink receivers coordinated in real-time. It accounts for uplink signal conditions at every sector receiving the mobile’s signal and determines the combined reliability.

Study Descriptions

Which sector to choose as the correct uplink sector for a given mobile/remote location depends on the technology or use-case in question. For example, in many cellular network types, the best downlink channel determines the uplink sector. In land-mobile systems using base-station voting receivers, the sector with the best received power from the mobile becomes the uplink sector, regardless of downlink power.

By default, the strongest downlink power determines the selection. This applies to uplink studies as well. So the Received power at best base from remote study, by default, selects the uplink sector based on the strongest downlink power. If sector uplink and downlink antennas differ, the study may report uplink power (or reliability) for a sector with sub-optimal uplink power. This represents correct behavior for many technologies because their downlink serves as the basis for parenting of subscriber devices. However, if you’re working with a technology that allows for independent uplink sector selection, then you may choose another study type to reflect this behavior.

The following sub-sections provide brief explanations of each SignalPro uplink study:

Received power at best base from remote

This study finds the sector with the strongest downlink power to that location, then finds and reports the uplink power (dBm) to that sector’s receive antenna.

Received voltage at best base from remote

This study finds the sector with the strongest downlink power to that location, then finds and reports the uplink voltage (dBuV) to that sector.

Received power at best voting receiver from remote

This study finds the strongest uplink sector for each location (regardless of downlink signal strength) and reports the uplink power (dBm) for that sector. This is the correct study for many land-mobile radio systems.

Uplink percent lognormal reliability

This study finds the sector with the strongest downlink power to that location, then calculates the uplink power to that sector and applies the lognormal fading method to find the percent chance that the uplink signal level may exceed the required service threshold on the sector receiver.

Uplink percent lognormal reliability using voting receivers

This study finds the strongest uplink sector for the location and uses the uplink received power along with the lognormal fading method to report the percent chance the signal level may exceed the required service threshold on the sector receiver.

Uplink percent lognormal reliability with Macro Diversity voting

This specialized study finds the combined reliability of all uplink sectors when the technology in question uses the uplink signal at all the base stations to reconstruct data from the mobile. This finds uplink signal powers for up to six contributing sectors (configurable under Study Preferences) and uses the lognormal reliability method to determine the percentage chance that the uplink signal may exceed the required signal threshold for any of the contributing sectors. To configure the number of contributing sectors, in the Menu Bar, select Studies > Study Preferences to display the Study Preferences dialog, similar to the following:

Open

Study Preferences Dialog

Conclusion

If you’re unsure which study type is appropriate for your use-case, don’t hesitate to reach out to the EDX Support team for assistance.