ZiPhone.org has uncovered code in the latest iPhone SDK beta that hints that the next generation iPhone will use Infineon's SGOLD3 (PMB8878) "3.5G" processor. From their marketing material:
INFINEON IS one of the early platform vendors to support HSDPA category 8 (7.2 Mbit/s). The implementation of equalizer based advanced receiver technology improves the data throughput, especially at high data rates, by up to 40%. In addition, the software programmable slot processing in the HSDPA Rx path provides further flexibility for performance enhancements. The HSDPA performance of S-GOLD3H meets and exceeds all test cases as specified in the 3GPP standard.
Unlike the EDGE-only chipset from the current Apple handset, the new Infineon hardware not only adds 3G over HSDPA but runs up to the international standard's newer 7.2 megabit per second spec -- twice the speed of the 3.6-megabit access seen on most HSDPA networks.
High-Speed Downlink Packet Access (HSDPA) is a 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family, which allows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacity. Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.4 Mbit/s. Further speed increases are planned for the near future. The networks are then to be upgraded to Evolved HSPA, which provides speeds of 42 Mbit/s downlink in its first release.