$section_ref = array();
$arResult['ROOT'] = array();
$section_ref[0] = &$arResult['ROOT'];
$rsSections = CIBlockSection::GetList($arOrder, $arFilter, false, $arSelect);//выборка разделов из бд в массив
while($arSection = $rsSections->GetNext()) {
	$section_ref[intval($arSection['IBLOCK_SECTION_ID'])]['CHILD'][$arSection['ID']] = $arSection;
	$section_ref[$arSection['ID']] = &$section_ref[intval($arSection['IBLOCK_SECTION_ID'])]['CHILD'][$arSection['ID']];
}
unset($sectionLinc);