Patents
According to the European Telecommunications Standards Institute's (ETSI) "IPR-database" (with "IPR" standing for intellectual property rights), about 50 companies have declared, as of March 2012, holding essential patents covering the LTE standard. The ETSI has made no investigation on the correctness of the declarations however, so that "any analysis of essential LTE patents should take into account more than ETSI declarations."
Read more about this topic: 3GPP Long Term Evolution