Unlike in 4G, PDCCH location in 5G is dynamic and to find need to learn about new terminologies like
- Search space
- CoreSet
this configuration is shared to device by gNB through RRC configuration messages and helps in finding the location of the coreset where PDCCH can be read.
lets dive into the configuration for pdcch config which itself is a combination of search space and coreset configuration.
coming to search space config from the image shown above first IE i.e monitoringslotperiodicityandoffset is a 2 value parameter, in the example shown indicates (2,1)
first value indicates the coreset periodicity i.e after how many slots coreset is repeated so here it is repeated in every 2nd slot and 1 indicates the slot offset so it repeats att 1,3,5..etc slots.
next Monitoringsymbolswithinslot is a 14 bit bitmap and each bit represents a symbol within a slot. here 4th bit set as 1. so coreset starts at 4th symbol.
ControlresourcesetID – is same id represented in controlresourcesetidtoaddmodlist(which talks about coreset params)
Duration says coreset duration here it spans in 6 symbols
and finally frequencydomainresources is a 45 bit bitmap and each bit corresponds to an RB i.e total 270 RBs within a bandwidth part. here 1st and 2nd bit are set as coreset occupies first 2RBs in frequency domain.
