Let me try to respond though it is a very broad question -
In access network there is not much change except the PDCP also appears between RRC and RLC/MAC though there is a change in the functionality of each protocol. (PHY is the major change which is OFDMA//SCFDMA as compare to WCDMA)
For detail please look at the following link http://www.freescale.com/files/wireless_comm/doc/white_paper/LTEPTCLOVWWP.pdf
In core network protocol part is changed a lot, whole SS7/SIGTRAN based stacks i.e. CAP/MAP/IN etc are replaced by the diameter based interface. RANAP is replaced by the S1AP, X1AP/X2AP are the new additions. GTP-C been upgraded to GTP-Cv2 and a lot more. Please see the following link for comprehensive picture (Page 9) http://hal.archives-ouvertes.fr/docs/00/83/06/21/PDF/RR-2013-02-RSM-LTEarchitectureandprotocol.pdf
what is difference between scheduling resource concepts and algorithms in LTE and UMTS HSPA+?
what is scheduling scenario for of nodeb-RNC and enode if you provide us with signalling message and mapping channels
LTE has a concept of default bearer while UMTS is not, want to know the details why the default bearer concept been added to LTE and what is the value it is adding to the overall system.