MSP430F5529: Suggest Ultra Low Power MCU

Part Number:MSP430F5529

Hello,

I am designing an IoT Low power wireless fill level measurement sensor which supplied with 3.6V LiSoCl2 Battery.The Hardware system describes that the level of garbage in the dustbins is detected with the help of Ultrasonic distance measurement (OWI), and communicated to the authorized control through Telit GSM Quadband (USART)Module so, Now I am using MSP4305529 MCU which is too large in size and Many peripherals resources are wasted for this product.

My Peripherals Details,

1.GSM Module (UART)

2.Ultrasonic AFE (OWI)

3.EEPROM (I2C)

4.GPIO up to 6.

So can anyone suggest me Best Low power MSP430 MCU in small size package and also LaunchPad board Availability Because I am using Energia IDE for Software development.