To say the legal battle between Apple and Qualcomm has been tense would be an understatement. The two companies have been after each other since January of this year, and it looks like the two are not showing signs of backing off or reaching a settlement.

Qualcomm Fires Back

On Wednesday, May 17 Qualcomm filed lawsuits against four Taiwan-based companies with ties to Apple. The companies in question are Foxconn, Compal, Wistron, and Pegatron, four of the manufacturers responsible for building iPads and iPhones. The lawsuit is for unpaid royalties owed to Qualcomm for use of its patented tech in Apple-branded smart devices.

The reason for Qualcomm going through these companies, rather than Apple, is because of the way Apple handles licenses. Rather than paying these license fees directly, companies and manufacturers pay the license to, say, Qualcomm, and Apple, in turn, reimburses said company. The lawsuit infers that Apple told the four companies in question to stop paying the license to Qualcomm and break the contracts with the San Diego tech company.

Heated Back And Forth

The whole legal battle began back in January, when Apple filed the first of many suits and countersuits. The first lawsuit claimed that Qualcomm had been asking and charging substantial royalties for tech licenses that weren't its own. Apple also claimed that Qualcomm owed it $1 billion, refusing to pay it due to Apple working with a Korean regulatory investigation into Qualcomm.

Qualcomm then fired back in April with a countersuit against Apple. In it, it claimed that Apple had conspired with other tech companies, like Samsung, to attack the company via a regulatory investigation and by providing false information to the investigators about Qualcomm.

During an investor call, Qualcomm also claimed that Apple was purposely withholding royalties. Apple said it's waiting until the legal dispute is settled before paying license fees. Qualcomm, on the other hand, said this is to force the chipmaker to agree to the license changes Apple wants from it.

Not The Only Front

This is only a part of the problem that has kept Qualcomm's legal teams busy. Just before the first Apple lawsuit was filed, the U.S. Federal Trade Commission filed an antitrust suit against the company, claiming that Qualcomm lowered license fees to drive manufacturers to it while forcing out competition. This had more fuel added to it when Intel and Samsung joined the FTC suit.

Right now, Qualcomm's chips are some of the most commonly used modem chips in phones, allowing them to connect to the different cellular networks available. But if any of these suits against Qualcomm are successful, the company could find itself in deep trouble.