Demo Functionality Overview#

The two demo applications provided showcase the following Bluetooth Low Energy localization features:

Distance measurement through Channel Sounding
Ranging Service (RAS) and Ranging Profile (RAP) implementation
Distance measurement data transfer through RAS
Complex-domain Distance Estimation (CDE) ranging algorithm
Rapid Accurate Distance Estimator (RADE) ranging algorithm

Application configuration options:

Channel Sounding role: Set the Channel Sounding role by using the gCsDefaultRole_c define in app_preinclude.h. In the default configuration, the loc_reader application is in the initiator role (gCsRoleInitiator_c) and the loc_user_device application is in the reflector role (gCsRoleReflector_c).
GATT CCCD type for RAS characteristics: Configure whether RAS characteristics use INDICATION or NOTIFICATION for data transfer by using the gRasUseNotifOrInd_c define in app_preinclude.h. Set to gCccdIndication_c for reliable delivery with acknowledgment (slower, guaranteed) or gCccdNotification_c for best-effort delivery without acknowledgment (faster, no guarantee). This affects RAS Control Point, Data Ready, Data Overwritten, and On-Demand Data characteristics. Default: gCccdNotification_c.
Channel Sounding procedure repeat: Use the Channel Sounding procedure repeat to specify the number of channel sounding procedures to be performed for each distance measurement triggered. This macro can be set through the gCsProcRepeatMaxNumProcedures_c define.
Ranging algorithm: The ranging algorithm must be run once the local and remote measurement data is available. Both supported algorithms can be disabled at compile time for code size reasons. By default, both are enabled. To disable an algorithm at compile time, define its respective macro with value 0 in the file app_preinclude.h. Use the macros gAppUseCDEAlgorithm_d and gAppUseRADEAlgorithm_d. At runtime, the setalgo shell command can be used to configure the algorithm that runs on completion of the CS procedure and RAS transfer. Any combination of algorithms can be selected.
Timing information display: To enable this feature, set the gAppCsTimeInfo_d macro to the value 1 in the app_preinclude.h file. The console then displays details of the timing information (such as the duration of the CS configuration phase, CS procedure, RAS transfer, and running of the algorithm(s)).
Data quality information display: This feature can be enabled by setting the gAppParseQualityInfo_d macro to the value 1 in the file app_preinclude.h for the Anchor. Additional information (such as RSSI and Tone Quality Indicator values for the measurement data) is displayed in the console.
GAP role: Set the GAP role using gAppIsPeripheral_d, 1 for peripheral role, 0 for central role. In the default configuration, the loc_reader application is central.
Maximum concurrent Channel Sounding procedures: Configure the maximum number of Channel Sounding procedures that can run simultaneously across all connections using the gChannelSoundingMaxConcurrentProcedures_c define in app_preinclude.h.
Adaptive Channel Sounding procedure interval (experimental): This experimental feature is disabled by default. When enabled (and the procedure auto-restart loop is active), the CS procedure interval is dynamically adjusted between loop iterations based on the remote RSSI average: a good RSSI decreases the interval (faster distance report rate), a bad RSSI increases the interval (more time for the RAS transfer to complete on a weak link), and an RSSI within the hysteresis band leaves the interval unchanged. CS procedures that fail to complete during an iteration are treated as a very bad link. To enable it, set the gAppAdaptiveProcInterval_d macro to the value 1 in the app_preinclude.h file; this requires gAppParseRssiInfo_d to also be enabled (enforced at compile time). The RSSI thresholds and interval limits (gAdaptiveRssiGoodThreshold_d, gAdaptiveRssiBadThreshold_d, gAdaptiveRssiNotCompleted_d, gAdaptiveProcIntervalStep_d, gAdaptiveProcIntervalMin_d, and gAdaptiveProcIntervalMax_d) can be tuned in application/common/lcl/app_localization_config.h.