Airtel Bangladesh
Airtel () in Bangladesh was managed by Bharti Airtel Bangladesh. Since 2016, the company of Bharti Airtel Bangladesh merged its operation into Robi Axiata Ltd. Therefore, the defunct Bharti Airtel Bangladesh company no longer exist and currently has been taken over and owned by Robi Axiata Ltd. 

Following the merger of Robi and Airtel, the merged company known as Robi Axiata Ltd. ‘Airtel’ will remain as a product brand of Robi Axiata.
Since then, Robi Axiata Ltd is the brand licensing holder for Airtel only in Bangladesh.

History 
In December 2005, Warid Telecom International LLC, an Abu Dhabi based consortium paid US$50 million to obtain a GSM license from the BTRC and became the sixth mobile phone operator in Bangladesh. Later Bangladesh operation of warid was rebranded to Airtel

Re-branding

In 2010, Warid Telecom sold a majority 70% stake in the company to India's Bharti Airtel Limited for US$300 million. Bharti's proposal also included an initial $300-million investment in Warid for creating new shares in the company. The Bangladesh Telecommunication Regulatory Commission approved the deal on 4 Jan 2010. Bharti Airtel Limited took management control of the company and its board, and re-branded the company's services under its own 'airtel' brand from 20 December 2010.

In March, 2013, Warid Telecom sold its rest 30% share to Bharti Airtel's Singapore-based concern Bharti Airtel Holdings Pte Limited for US$85 million.

On 8 September 2013, Airtel Bangladesh received 5 MHz of the 3G spectrum at US$1.25 million.

Merger Details
In January 2016, Robi and Airtel Bangladesh announced that they intended to merge their operations in Bangladesh, that the combined entity would be called Robi, which would serve about 32 million subscribers, and in which Axiata Group would own 68.7% of the shares, Bharti Group would own 25.0%, and the remaining 6.3% owned by NTT DoCoMo. The merger was completed in November 2016.

Airtel User's on Robi Network 
As Airtel merged into Robi Axiata Limited, Existing airtel users will be connected to Robi Network Automatically. 
But If automatic network registration fails in any phone & no signal appears, following this step will help to get Robi Network. 
 Open Your Phone > Settings Option > Network Settings > Mobile Network > Search Manually : You may find robi network, connect with it.

 If you want to use internet, enable data roaming option.

See also
 Airtel Africa (Bharti Enterprises Ltd)
 Airtel India (Bharti Enterprises Ltd)
 Airtel Sri Lanka (Bharti Enterprises Ltd)

References

Mobile phone companies of Bangladesh
Bangladeshi subsidiaries of foreign companies
Bharti Airtel