The United Nations Office at Vienna (UNOV), acting on behalf of the United Nations Office on Drugs and Crime (UNODC) and the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO)—all situated at the Vienna International Centre in Vienna, Austria—hereby invites qualified and independent mobile telecommunication service providers to submit Expressions of Interest (EOI). he purpose of this EOI is to identify mobile network operator capable of delivering reliable secondary global mobile voice and data services. These services will function as a robust backup to the existing primary mobile service provider, ensuring uninterrupted operational continuity under all circumstances. Interested vendors are advised that this notice constitutes an Expression of Interest only and does not represent a solicitation of bids or a request for proposals. Accordingly, detailed specifications, terms of reference, and tender documentation are not included at this stage. Such documents will be issued only to vendors who are invited to participate in the subsequent formal solicitation process. Suppliers wishing to express their interest are requested to do so exclusively via the United Nations Global Marketplace (UNGM). Specific Requirements/Information Detailed requirements will be provided with the Request for Proposal