The Research Of Extended Uplink TBF Mode

GPRS is the abbreviation of General Packet Radio Service. Data transmission in circuit–switched mode has the drawback to allocate resources during the whole session, GPRS defines a network architecture dedicated to packet transfer mode, with radio access, which allows service subscriber to send and receive data in end-to-end packet transfer mode, without utilizing network resource in circuit-switched mode.Alcatel Shanghai Bell is constantly developing the technologies of (E)GPRS network to provide better network. Extended Uplink TBF (Temporary Block Flow) release technology is one of the most important technologies.Now, we are still use the normal UL TBF release mode: When a MS reaches the end of an UL TBF, it starts a"countdown procedure"whereby it indicates to the network the number of remaining RLC blocks it has to send. Once all these PDUs have been successfully transmitted to the network, the MS releases the UL TBF. The main drawback is that it is not possible to restart the countdown procedure once it has been started and that it leads to the UL TBF release. Thus, all new PDUs coming after the start of the countdown procedure cannot be transmitted in the current TBF. A new one shall be requested and established, which is time consuming.Extended UL TBF Release mode resolves this problem. Main principle of the Extended UL TBF Release is that:UL TBFs are maintained established some times after the last UL radio block has been sent by the MS. This is called the"Extension Phase"(The MS is said to be in'Extended Mode"). Therefore when a new UL PDU has to be sent during the extension phase, the MS has no more to establish a new TBF, it uses the extended UL TBF. The resulting benefit is a quicker UL traffic resumption, beneficial to applications requiring a high reactivity (e.g. WAP, ping).Also during the extension phase, any new DL PDU to be sent for the same MS requires only to establish a DL TBF on PACCH (in concurrence of the UL TBF), which is quicker than establishing the DL TBF through the common channels (which happens when there is no established UL TBF).The MS is aware that the BSS supports the feature through a new parameter sent on System Information (SI13, or PSI in case a Master Channel is activated in the cell).The feature is supported only by MS support of the GERAN feature Package 1.The BSS knows that a MS is compatible with the feature through the MS Radio Access Capability IE present in the DL PDU received from the SGSN. However, to workaround some situations where the first DL PDU may be received later (e.g. cell re-selection on a UL biased transfer), the BSS is able to retrieve the MS capabilities through the MS RA Capability Update request that it sends to the SGSN. This procedure is used by the BSS when the O&M parameter EN_RA_CAP_UPDATE is set.The thesis will discuss the procedure of Extended UL TBF Release mode, the relation between Extended UL TBF Release and other new technologies and the system impacts towards network .I test the Extended UL TBF Release feature in the ALCATEL BSS B9 software. I will analyze the test case in this thesis.To sum up, based on the fact that (E)GPRS is still the preferred mobile telecommunication technology and will be the effective supplement of 3G mobile telecommunication technology. Developing Extended UL TBF Release technology is very important.