ental redundancy. If Node B never receives any ACK/NACK, it should retransmit using another self-decodable rate matching scheme. B.3.5 Fast Packet Scheduling The objective of the packet scheduler is to optimise the cell capacity while delivering the minimum required service experience for all active users excluding an allowed outage target. Outage is defined from blocking, dropping and QoS requirements related to a given application. Internet server Node-B L1 retransmissions TCPlayer retransmissions. (incl. slow start effect) RLC layer retransmissions Figure B.3 HSDPA retransmission breakdown Main Changes in HSDPA Table B.3 Hacket scheduler strategies Packet scheduler Selection metric Scheduling rate Fairness/performance Fair throughput (FT) The user with least Fast (2-20ms basis); Same average user throughput is in R99 architecture throughput over scheduled this is slow activity time Fair resource (FR) or Round-robin in random Fast (2-20 ms basis); Same average physical round-robin in time order in R99 architecture resources but uneven this is slow user data rates Maximum C/I (M-C/I) Maximising Fast (2-20 ms basis) Optimum cell capacity or maximum throughput or but very uneven user throughput (M-TP) channel quality data rates and limited coverage Proportional fair Ratio of instantaneous Fast (2-20 ms basis) Approximately same resource to average average physical throughput (relative resources and instantaneous uneven user data channel quality, or rates (fairer than fair RICQ) resource PS) with very high capacity The actual packet scheduling algorithm is not specified in 3GPP and there is a large degree of freedom available to manufacturers. However, with the definition of various QoS parameters such as discard timers and guaranteed bit rates, it is expected that the packet scheduler does its best to fulfil the requirements given for any user. This is especially significant in multivendor environments (e.g. RNC and node B from different vendors) where the QoS responsibility is distributed. The packet scheduler ne