Combine hex-to-string function with encoding conversion. In this example, the source string Unicode string encoded in hexadeciaml. The following code decodes it and convert it to UTF-8 string.

Unicode Hexadecimal To UTF-8 String Conversion

<?php
function hexToStr($hex){
    $string='';
    for ($i=0; $i < strlen($hex)-1; $i+=2){
        $string .= chr(hexdec($hex[$i].$hex[$i+1]));
    }
    return $string;
}

$s = '6df157335e0253575c71533a53576d7759279053003100300037003953f7002000200068007400740070003a002f002f007700770077002e006700700073002e0063006f006d002f006d00610070002e0061007300700078003f006c00610074003d00320033002e0031003200330026006c006e0067003d003100310033002e003100320033';

echo mb_convert_encoding(hexToStr($s), 'UTF-8', 'Unicode');
// Output: 深圳市南山区南海大道1079号 http://www.gps.com/map.aspx?lat=23.123&lng=113.123