I don't recall Apple buying anything two decades ago -- communication patents much less -- Jobs was still busy cutting fat at Apple around that time. Are you talking about the wireless patents bought from the Nortel Bankruptcy in 2012, via Rockstar Consortium to which both Apple and Microsoft were founding members?
Sure, cross-licensing can sometimes be used as a negotiation chip in different situations, but, considering what Samsung and LG, who are among the top LTE patent holders were getting in return for cross-licensing with QUalcomm, I doubt that Infineon's patent portfolio was much of value. Also remember that the wireless SEP royalties are collected at the end of the supply-chain, ie, handset OEMs -- Qualcomm is not a handset OEM and has little or nothing to gain from such negotiation. Infineon's patents had very limited utility (and I'm pretty sure Apple's lawyers knew that too).
And Apple was the largest stakeholer in the Rockstar Consortium and, from the very getgo, Apple never intended to use them as a defense against Qualcomm (or any potential patent lawsuit). The Rockstar was a patent troll operation concocted by Apple to harasse Apple's competitors -- ie, Google and Android OEMs. It's just too bad that, despite Judge Gilstrap's heroic defiance to keep the case in Texas, judge Wilkens in the California court correctly saw through Apple's garbage and brought back the case home where all parties and witnesses, including Apple, would have been required to testify. Of course, the Rockstar dropped the lawsuit like a rock to prevent public disclosure of Apple's shenanigan.
Having observed Apple's lawsuits past 10+ years, I think it's silly to describe Apple's patent strategy as anything other than "predatory;" I certainly wouldn't call it "defensive."