For the past two-plus years, the Iranian Army ground forces have been engaged in the process of reorganizing their forces away from a division-centric, to brigade-centric model. This is hardly a novel concept - Iran follows in the footsteps of both the Spanish, and U.S armies. However, instead of producing medium-weight expeditionary forces (i.e Stryker brigades), this transformation ass been geared toward fighting a defensive war against modern maneuver army.
Until recently the army has maintained the same division-centric model it inherited from the imperial Iranian army, and fought their war with Iraq with. These were comprised of three combat brigades with the usual range of divisional-level support company/battalions. The purpose of the divisional staff was to coordinate combined arms operations between the brigades and support assets.
Now, however, brigades rather than divisions are the basic combat unit capable of carrying out sustained combat operations. On Army Day 2012 General Pourdastan announced that in 2011 (1390) the Army had a total of 19 independent brigades, while 12 more would be created in 2012 (1391). Of the 19 pre-existing brigades, we can identify the 37th (Shiraz) and 38th (Torbat Jam) independent armored brigades (IAB), the 40th (Ardebil), and 41st (NW Iran) independent infantry brigades (IIB), the 71st (Sarpol Zahab) independent mechanized infantry brigade (IMIB), the 11th (Maragh), 22nd (Shahreza), 33rd (Tehran), 44th (Isfahan), and 55th (Isfahan) independent artillery groups (IAG), and the 25th (Pasveh), 35th (Kermanshah), 45th (Dezful), 55th (Shiraz), and 65th (Tehran) commando/airborne brigades (ICB/IAbnB). The identities of four brigades remain unknown; they may include engineering, or air-defense brigades.
The 12 new independent brigades have been formed by shearing them off from existing divisions, which have now been reduced to two brigades in strength, or effectively abolished altogether. Newly independent brigades include the 284th IIB (Lorestan), 228th, 216th IAB (Zanjan), 277th IIB (Quchan), 177th IIB (Torbat Heydariyeh), 288th IAB (Khash), 130th IIB (Bojnourd), 221st IIB, 264th IIB (Urmia), 281st IAB (Kermanshah/Bistoon), and 292nd IAB (Dezful). Convinently, the last two letters of the brigade's numerical designation corresponds to their parent unit, making identification relatively easy. For instance, both the 277th and 177th IIBs were formed from the 77th MID, while the 288th and 292 IABs were, respectively, once part of the 88th and 92nd ADs. Furthermore, these many of these newly independent brigades are relocating away from their historical garrisons inside cities toward new bases outside of the congested urban environment.
At the regional level, these combat units are supported by an increasing number of independent support brigades - artillery groups being the most well-known examples. While these brigades existed before, they are now being relocated away from large, centralized garrisons in places like Isfahan and Tehran towards forward deployment in border regions. At least two have been re-deployed in the eastern cities of Khash and Qaen.
According to General Pourdastan, this reorganization was the product of internal study of past wars, particularly those involving western-style maneuver forces. The conclusion drawn was that if Iran wanted to defeat a modern NATO-type army, such as the one that faced Iraq in 1991 and 2003, their organizational structure (aka C2 hierarchies) would have to be made resilient against concentrated, high-density firepower. In essence, Iran is trying to prevent the U.S from being able to achieve battle-space (aka 'information')-dominance.
That fact that these concepts have been trivialized as buzzwords does not take away from their real world power. By controlling your enemy's vision of the battle-space, you are ensuring that he will always be reacting to the way the battle used to be, not the way it is. The quintessential example of this is from 1991 in which coalition forces were able to simultaneously maintain total situational awareness through tactical communication, while degrading the Iraqi's C2-network. British General Rupert Smith recounts one example where Iraqi tankers had been ordered to attack a breach that had occurred "...24 hours previously and 100 kilometers back.", but because their staff didn't have an accurate picture of the battle the unit in question wandered blindly into prepared (aka situationally-aware) British forces and where destroyed. (The Utility of Force, 51)
To see how this strategy might be negated at a conceptual level, one has only too look to the 2006 Lebanon war in which Hezbollah was able to defeat Israel's military strategy because they controlled the information battleground. By practicing adept denial-and-deception, and 'shoot-and-scoot' operations, Hezbollah was able to deny Israel - including their air-based surveillance platforms - an accurate picture of the battlefield at an operational level. This meant that the IDF, like the Iraqis, had given up the initiative to their enemies, allowing them to control the tempo and flow of the battle.
To this end, Iran's reorganization can be seen as flattening decision making by giving brigade commanders a larger tool-box that can be called upon without relying on divisional-C2 to remain intact. Pourdastan has consistently described the motivation behind such a move as boosting unit's tactical/operational flexibility, making them better equipped to respond self-sufficiently to these kind of "critical situations" imposed by todays rapidly changing battlefield.
Historically, the divisional hierarchy arose as the most efficient way to manage the rapid expansion in the size of national armies following the Napoleanic revolution in military affairs. At this time, the corps-level staff simply couldn't coordinate the number of troops in action as well as the growing density of firepower available to these combat units (independent artillery units being the best example). The division solved this problem by pushing the coordination of combined arms 'down' a level, preventing total organizational paralysis that would have resulted should C2 remained centralized at the corps level.
However, the success of such a system still depends heavily on intact C2-structures, and as national armies have shrunk in size since the high-water point of WWII and the Cold War, the same problem of combat unit flexibility has again reared its head, exacerbated by Western information-dominance strategies, which seeks to exploit this inherent weakness in all hierarchies.
Shifting toward independent brigades pushes 'combined arms coordination' down another level. Thus, in Iran we should expect brigades to now field a more robust level of organic artillery, air-defense, anti-tank, and engineering support. While the ORBAT of Iranian divisions is not well known, several guesses can be made which, if nothing else, will illustrate the principal behind the reorganization. Until recently the brigades belonging to the 30th ID have relied on divisional-level heavy transport to ferry its motorized infantry battalions. Now that the 130th brigade is now independent, we should expect it to be able to provide its own operational transport, allowing it to function where before they could have been rendered impotent by destroying (electronically or kinetically) the C2 links between Bojnourd and Gorgan.
For an excellent description of the implications of information-dominance and control of the battle-space-image, consider reading this piece on network-centric warfare from Australia Airpower.