[[Image:cdma19.jpg]]
==Quality of Service(QoS)==CDMA is being accepted as a third -generation system and a specific feature of 3G system is that it offers a radio interface adapted for all kinds of services and combination of services(data,voice,image video, etc.). The big issue is of multiplexing of these services which have do not have the same demands in terms of quality of service(QoS) which can be represented as BER(bit error rate),processing delay,frame error rate etc. Different QoS will require different channel encoding and interleaving strategies. The demand of BER can be satisfied when the coding bits have atleast a code dependent ratio Eb/I(ratio of bit energy to interference). There are several influences that might change system performance(BER) and hence Eb/I ratio, of which the most effective is variation of Bit Rate by a step of '''Rate Matching'''. <br><br>
===Rate Matching and QoS===
The patent '''EP 1385290 titled Method for balancing Eb/I ratio in a service multiplexing CDMA system and a telecommunication system using this method''' targets at this concept of Rate matching and introduces an algorithm of calculating effective data output bits by a process of repetition or puncturing of the input bits governed by a '''rate matching ratio''' and '''puncturing ratio''' received from the sending entity(can be BS or MS). The following framework highlights the various steps involved in providing variable QoS.