The Brnjica culture (1400bc-1100bc) is one possible explanation for the origin of the Paeonians, with the other main candidate being the Ulanci group of Matt-Painted ware.
At the end of the Late Bronze Age, three different groups occupy Macedonia in quick succession:
-1600-1200bc: Matt Pained ware (Ulanci)
-1250-1100bc: Brnjica Culture
-1150bc-1100bc: Belegis/Channelled Ware Culture
"After the intensive development during the Late Bronze Age, almost simultaneously, all settlements in the Vardar Valley were forcibly destroyed and were not rebuilt. Their cemeteries also ceased to be used during the same period.
Only in a few exceptions, such as the settlement of Tumba-Kastanas, which, being an island in the Vardar River, was naturally well-protected and economically stronger, life continued, albeit with lasting consequences.
During the 12th and 11th centuries, the settlement of Tumba-Kastanas was 4 times repeatedly and consecutively destroyed by fire and always rebuilt. However, with each rebuilding came dramatic changes and the appearance of numerous new elements introduced from the north through the Morava-Vardar Valley."
(ARCHAEOLOGICAL DATA ON THE GREAT AEGEAN MIGRATIONS By Dragi Mitrevski)
This also fits the time frame for when the Iliad would have taken place (~1190bc), which gives a mention of the Paeonians, as allies of the Trojans.
The Ulanci Culture has its roots in the local Matt-Painted ware, which is found across all of Macedonia, Northern Greece and southern Albania. This culture is likely the Phrygians and Bryges prior to their migration to Anatolia (and we also do find Matt-Painted ware in Central Anatolia in the 9th century BC, which is when the Phrygians reached it. There is also Matt-Painted ware in Southern Italy, although it is unrelated to the Macedonian Matt-Painted ware and is a local Italian imitation derived from Italian Ware to compete with Greek Geometric Workshops.)
The Brnjica culture develops locally out of the Paracin culture and the late Bubanj Hum IV-Ljuljaci group, with influences from the Urnfield and Belegis I complexes. It starts a southward expansion in around 1250bc, likely from Pressures by the expanding Belegis II Culture, the catalyst of the Channelled ware horizon, to their north.
The Belegis II Culture, on the other hand, is a local development of the Belegis I culture with influences from the Velatice group of the Urnfield Culture, whence it gets its characteristic Channelled/Fluted Decoration from, and the Encrusted Ware groups on the Danube. The Belegis Culture starts a aggressive expansion Northward along the Tisza and Mures, Eastward along the Danube into Moldova (forming Babadag I, Chisinau Corlateni, Tamaoani-Holercani, Hansca Balta and possibly Vartop) and Southward along the Morava, penetrating deep into Macedonia, likely becoming a part of the Sea Peoples in the Process, with Belegis II-derived Hand Knobbed Ware being found all across Greece and even in Crete.
The Belegis II Culture's occupation of the Morava-Vardar is however very short, and its bearers do not persist into the iron age. During the Iron Age, Matt-Painted pottery becomes characteristic of Macedonia again, possibly arguing for a Survival or resettlement of the Ulanci cultures people.
The Conclusion is that there are three groups during the time of the Paeonians first mention in the late bronze age, all which could have become the Paeonians in the Iron Age, with the Ulanci Matt-Painted groups being the safest candidate, however not certain.
===============
All Maps depicted are available on Maptism.
-Florian Ruppenstein, "The migration events in Greece at the end of the second millennium BC as the last result of a domino effect?"
-Dragi Mitrevski, "ARCHAEOLOGICAL DATA ON THE GREAT AEGEAN MIGRATIONS"
-Dragi Mitrevski, "The Beginning of the Iron Age in Macedonia"
-Dragi Mitrevski, "Burial Practices and Customs in Macedonia in the Transitional Period from the Bronze to the Iron Age"
-Milorad Stojic, "THE BRNJICA CULTURAL GROUP IN THE SOUTH MORAVA BASIN"
-Milorad Stojic