Wa 'alaikkumus salaam wa rahmathullah, it is not a pillar of the salaah nor is it an obligation of the prayer to be accepted, which means if you forget to do the iqamah or adhan even in a congregation, then this not affect the validity of the prayer. As Shaykh `Abdul-`Azeez Bin Baz mentions :The Iqamah is not prescribed for the single worshipper, whether man or woman, since the Iqamah is an announcement to the congregation that the prayer is about to start, so the solitary worshipper does not need it; and if a congregation prayed without Athan or Iqamah, it would not affect their prayer, because the Athan and Iqamah are not conditions for the acceptance of prayer, nor are they pillars of prayer.
As for if a person should do the adhaan and iqamah before praying, then this is mustahabb/preferred(and I suppose Shaykh Al Albaanee hold the view it is obligatory) .
Al-Shaykh Mansoor al-Bahwati (may Allaah have mercy on him) said:
“They (the Adhaan and Iqaamah) are Sunnah (for the person who is praying alone) because of the general meaning of the hadeeth of ‘Uqbah ibn ‘Aamir, who said that the Prophet (peace and blessings of Allaah be upon him) said: ‘Your Lord likes it when a shepherd at the top of a mountain pass calls the Adhaan for prayer and then prays. Then Allaah says, “Look at this slave of mine, saying the Adhaan and the Iqaamah for prayer and fearing Me. I ask you to bear witness that I have forgiven My slave and will admit him to Paradise.”’” (Narrated by al-Nisaa’i). The Adhaan and Iqaamah are also Sunnah for travellers, because the Prophet (peace and blessings of Allaah be upon him) said to Maalik ibn al-Huwayrith and his cousin: “When you two travel, say the Adhaan and Iqaamah for prayer, and let the elder of you lead the prayer.” (Agreed upon). Mutaalib Oolaial-Nuha, part 1, Baab al-Adhaan.
And the other opinion that it is obligatory to do the adhaan or Iqaamah before you pray is...
