RFC: API for Neighbouring Cell Info

[Bastian, Waldo]

Hi all,

I would like to propose an API for exposing neighbouring cell info. 
Since the exact information provided is rather modem specific my thinking is to use the following API as the generic framework and then the actual per-cell information attributes that a driver provides can be different from modem to modem with the constraint that _if_ a modem provides a certain attribute that is specified by this API definition the driver must format it as specified.

Your feedback is highly appreciated, especially from those who plan to use this information for location purposes.

Once there is agreement on the API we can discuss whether it makes sense to add some skeleton support in the oFono core or leave it to each individual modem plugin to implement the DBUS service in its entire.

Cheers,
Waldo


Neighbouring Cell Info hierarchy
=================================

Service		org.ofono
Interface	org.ofono.NeighbouringCellInfo
Object path	[variable prefix]/{modem0,modem1,...}

Methods	dict GetProperties()

			Returns all neighbouring cell info properties. See the
			properties section for available properties.

			Possible Errors: [service].Error.InvalidArguments

		void SetProperty(string name, variant value)

			Changes the value of the specified property. Only
			properties that are listed as read-write are
			changeable. On success a PropertyChanged signal
			will be emitted.

			Possible Errors: [service].Error.InvalidArguments
					 [service].Error.DoesNotExist

Signals	PropertyChanged(string property, variant value)

			This signal indicates a changed value of the given
			property.

Properties	boolean Enabled [readwrite]

			Boolean representing whether the interface provides
			neighbouring cell information.

		array{dict} Info [readonly, only when Enabled]

			List of neighbouring cells with the following information for each cell:

			string Type [readonly]

				Describes the type of Cell.

				The possible values are: "GSM serving cell",
						"GSM neighbour cell",
						"UMTS serving cell",
						"UMTS neighbour cell",
						"UMTS detected cell"

			string MobileCountryCode [readonly]

				Contains the Mobile Country Code (MCC).
	
			string MobileNetworkCode [readonly]

				Contains the Mobile Network Code (MNC)

			uint16 LocationAreaCode [readonly]

				Contains the location area code of the cell.

			uint32 CellId [readonly]

				Contains the network cell id.

			byte RxLevel [readonly, GSM only]
		
				Received signal strength as defined by [3GPP TS 45.008 s8.1.4] [0-63]			

			uint32 TimingAdvance [readonly, GSM serving cell only]

				Timing advance for serving GSM cell [0-???]

			uint16 ScramblingCode [readonly, UMTS only]

				Scrambling code [0-511]

			uint16 DownlinkFreq [readonly, UMTS only]

				Downlink frequency [0-16383]

			int8 RSCP [readonly, UMTS only]

				Received Signal Code Power [3GPP TS 25.133 s9.1.1.3] in dBm [-120...-25]

			int8 ECNO [readonly, UMTS only]

				CPICH Ec/No [3GPP TS 25.133 s9.1.2.3] in dB  [-24...0]