3GPP Mindsets: Voice and Data – Past and Present

Quite often I discuss with colleagues and friends what went right and wrong over the years in 3GPP standardization. We usually agree that the first version of UMTS didn't get the data part quite right and that the first version of LTE has a serious problem with missing voice capabilities. Recently a friend said 'When 3G was designed, data was forgotten. When 4G was designed, voice was forgotten'. At first, I agreed to this but after some more reflection I think it doesn't quite hit what's happened.

I still remember vividly that when the 3G UTRAN (UMTS Terrestrial Radio Interface) was first designed, it was done with the purpose to add data capabilities beyond what was possible with 2G GPRS at the time. From that point of view, 3GPP has succeeded, because the 384 kbit/s downlink speed reached by first networks was an order of a magnitude higher than what was possible with GPRS at the time. However, the mindset at the time was still very much focused on dedicated channels on the air interface. So this was the method of choice for data transmissions despite the rest of the network being packet switched. Unfortunately, this lead to a very inefficient use of the air interface for packet data transmission such as web browsing with the resulting limitation in speed and number of simultaneous users. The situation was eventually fixed with the introduction of high speed shared channels, known as HSPA today.

Fast forward 10 years and we are now in the days of E-UTRAN, aka, LTE standardization. This time, the mindest was on packet switched only, at any cost. The cost was the 'down to earth – works out of the box' voice capability, which is sadly missing so far. I am sure there are quite a number of reasons for this but I think one of the main ones is that a majority of the companies in 3GPP are pushing for IMS and have been vehemently against any other form of voice capabilities. Other companies have made good suggestions, such as connecting the MSC to the E-UTRAN but so far the suggestion went nowhere.

Well, I guess it will be as in the case of UTRAN: A second round might be required before LTE can truly succeed UMTS.