A method (300, 400, 500, 600) implemented by a network device in a communication network, the network device operable to communicate with a User Equipment UE and a Narrow Band Internet Of Things, NB-IoT, terminal device in the communication network, the method comprising: configuring NB-IoT Physical Resource Blocks PRBs (301, 401, 501, 601); wherein said NB-IoT terminal device is deployed in in-band mode; when scheduling said UE, if said configured NB-IoT PRBs have not been allocated to said NB-IoT terminal device and if available PRBs other than said configured NB-IOT PRBs are not enough for said UE, attempting to allocate said configured NB-IoT PRBs for said UE, characterized by said attempting to allocate said configured NB-IoT PRBs for said UE comprising: scheduling said UE including said configured NB-IoT PRBs (402,602); and if a modulation and coding scheme MCS scheduled by said network device for said UE is greater than a first threshold or if a number of PRBs allocated for said UE is smaller than a second threshold, rescheduling said UE by removing said configured NB-IoT PRBs from the allocated PRBs (403a, 603a); or if said MCS scheduled by said network device for said UE is smaller than said first threshold and if said number of PRBs allocated for said UE is greater than said second threshold, keeping using said configured NB-IoT PRBs for said UE (403b,603b); or if a MCS scheduled by said network device for said UE is smaller than a third threshold and if a number of PRBs allocated for said UE is greater than a fourth threshold, carrying Narrow Band Reference Signals NRSs in said configured NB-IoT PRBs; or if said MCS scheduled by said network device for said UE is greater than said third threshold or if said number of PRBs allocated for said UE is smaller than said fourth threshold, muting said NRSs in said configured NB-IoT PRBs. configuring NB-IoT Physical Resource Blocks PRBs (301, 401, 501, 601); wherein said NB-IoT terminal device is deployed in in-band mode; when scheduling said UE, if said configured NB-IoT PRBs have not been allocated to said NB-IoT terminal device and if available PRBs other than said configured NB-IOT PRBs are not enough for said UE, attempting to allocate said configured NB-IoT PRBs for said UE, characterized by said attempting to allocate said configured NB-IoT PRBs for said UE comprising: scheduling said UE including said configured NB-IoT PRBs (402,602); and if a modulation and coding scheme MCS scheduled by said network device for said UE is greater than a first threshold or if a number of PRBs allocated for said UE is smaller than a second threshold, rescheduling said UE by removing said configured NB-IoT PRBs from the allocated PRBs (403a, 603a); or if said MCS scheduled by said network device for said UE is smaller than said first threshold and if said number of PRBs allocated for said UE is greater than said second threshold, keeping using said configured NB-IoT PRBs for said UE (403b,603b); or if a MCS scheduled by said network device for said UE is smaller than a third threshold and if a number of PRBs allocated for said UE is greater than a fourth threshold, carrying Narrow Band Reference Signals NRSs in said configured NB-IoT PRBs; or if said MCS scheduled by said network device for said UE is greater than said third threshold or if said number of PRBs allocated for said UE is smaller than said fourth threshold, muting said NRSs in said configured NB-IoT PRBs. scheduling said UE including said configured NB-IoT PRBs (402,602); and if a modulation and coding scheme MCS scheduled by said network device for said UE is greater than a first threshold or if a number of PRBs allocated for said UE is smaller than a second threshold, rescheduling said UE by removing said configured NB-IoT PRBs from the allocated PRBs (403a, 603a); or if said MCS scheduled by said network device for said UE is smaller than said first threshold and if said number of PRBs allocated for said UE is greater than said second threshold, keeping using said configured NB-IoT PRBs for said UE (403b,603b); or if a MCS scheduled by said network device for said UE is smaller than a third threshold and if a number of PRBs allocated for said UE is greater than a fourth threshold, carrying Narrow Band Reference Signals NRSs in said configured NB-IoT PRBs; or if said MCS scheduled by said network device for said UE is greater than said third threshold or if said number of PRBs allocated for said UE is smaller than said fourth threshold, muting said NRSs in said configured NB-IoT PRBs.