What kind of information is carreid by each DCI ?.This is a kind of blessing to me.Īs one example showing how/when DCI is used, refer to " Uplink Data Transmission Scheduling - Persistent Scheduling" Have to care anything about configuring these things in RRC messages. And other complication was that even in HSDPA we still using R99 DPCH for power control and signaling purpose, so I cannot completely remove the headache of handling TFCS.Now in LTE, this information is carried by DCI as I explained above and we only have to care about just a couple of parameters like Number of RBs, the starting point of RBs and the modulation scheme and I don't but still I need to jump around the multiple different 3GPP document to define any meaningful TFRIs. The resource allocation information carried by HS-SCCH is called 'TFRI'. HSDPA relieved the headache a lot since it carries these information directly on HS-SCCH and this job is done by MAC layer. A lot of error meaning headache came from the mismatches between the TFCS information you configured in 元 message and the configuration the transmitter applied to itself (transmitter's lower layer configuration). Have to configure itself according to the table. You had to define all the possible combination of resource allocation in the form of TFCS (a kind of look-up table for TFCI) and you have to convey those information through 元 message (e.g, Radio Bearer Setup message and RRC Connection Setup message) and the transmitteralso In terms of protocol implementation with respect to carrying these information, R99 seems to be the most complicated one. This question will be answered in later part in this page. Then Question would be which DCI format we have toįor a specific situation. There are several different DCI format, each of which has different set of intormations it can carry. In addition to resource allocation, it can carry Power Control Command, CSI Report Request or CQI Report Request etc. For example, in WCDMA R99, Slot format and TFCI carries those information and in HSDPA HS-SCCH carried those information and in HSUPA E-TFCI carries it.Ĭomparing to control channel in other technology (WCDMA, HSPA), LTE DCI has a lot more additional information in it. Not only in LTE, but also in most of wireless communication the reciever requires special information structure like DCI. It means you (the reciever) first have to decode DCI and based on the information you got from the DCI you can decode the real data. It is DCI which carries those detailed information like "which resource block carries your data ?" and "what kind of demodulation scheme you have to use to decode data ?" and some other additional information. This is where the term called 'DCI(Downlink Control Indicator)' comes How can the other party (the recieving side) can figure out exactly where in the slot and in which modulation scheme that the sender (transmitter) transmit the data(subframe)? I just captured the physical signal but how can I (the reciever) decode this signal. ![]() Then you would have this question (At least I had this question). ![]() ![]() Of all the possible permutation of these variables, the number of possible resource allocation will be very huge. Especially in frequency domain, you have so many resource blocks you can use (100 Resource Blocks in case of 20 Mhz Bandwidth) and if you It was combination of Time Domain, Frequency Domain and the modulation scheme. When you study the physical frame structure of LTE, you may be impressed by flexibility (meaning complexity in other way) of all the possible ways of resource allocation.
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