"Procedure for Radio Frequency Licensing" - Part 1 and Part 2 - in English, Ministry of Posts and Telematics (no date). Part 2 includes a short section on "Types of Radio Equipment Subject to Conditional Use and Requiring No Licenses." All the version currently online says is that "In each period, the Ministry of Post and Telematics shall prescribe and publicize the list of radio equipment subject to conditional use..."
Asia Telecommunication Newsletter, 23 May 2003. According to the US State Department, "Vietnam does not yet permit unlicensed radio-frequency spectrum for use by Wi-fi, but does for use by some cordless telephones... Recently, MPT [the Ministry of Posts and Telematics] has approved radio-frequency spectrum of the 2.4 GHz - 2.4835 GHz range for use by Wi-fi products...but on a case-by-case basis. Vietnam has not licensed 802.11a products to operate in the 5 GHz range... MPT has no plans at this time to authorize Wi-fi services as low-power devices..."
"Chủ đề: Các vấn đề về phí tần số" - this appears to be a list of questions asked in email messages from Vietnamese citizens about the rules for Wi-Fi, WLANs, ISM, Citizens Band radio, etc., with answers (in Vietnamese) from the Radio Frequency Department of the Ministry of Posts and Telematics. An answer dated 19 December 2005 seems to identify these bands as available for use by local wireless data networks: 2400-2483.5 MHz, with a power limit of 100 mW (20 dBm); 5150-5250 MHz and 5250-5350 MHz, with a power limit of 200 mW (23 dBm); and 5725-5850 MHz, with a power limit of 1W (30 dBm).
"VDC introduces WiFi technology,"Vietnam News, 23 August 2003: "In preparation for the Southeast Asian Games, the Vietnam Datacommunications Co and Intel Vietnam plan to develop 100 Wireless fidelity (WiFi) hotspots. The new internet service centres will be in hotels, airports, railway stations, press centres, and stadiums... The company plans to install a total of 1,000 hotspots nationwide during 2004-2005."