Can ENB receive data during UE's DRX off duration?

Question

suppose UE is in DRX mode and went to sleep. If UE sends any data to ENB, Will the ENB receives this data or just ignore as it is in idle state?

Answer 1

In drx dle mode, ue can send data ul and enb will receive data . So if ue have data to send in ul during drx sleep cycle then ue can come out from sleep to active mode. Then ue needs to send sr to enb to get ul grant . After getting ul grant , ue will send data in ul.

Comments

If UE is able to send data in idle mode, then How it saves the battery? What is the use of IDLE mode, can you please elaborate ?

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If there is not data then UE should save the battery. But if have the data in UL then why need to same battery.

if UE is in idle mode then eNB can not schedule the DL data . eNB will wait for active mode. This will saving the battery.

Answer 2

UE cannot send data in IDLE mode, but it can listen to paging msg , but if UE has some data with it, it has to ask for GRANT from N/w and has to use some battery.

Comments

Though I don't have more knowledge on eNodeB protocol. But I can say there are two types of DRX. The one which is used by UE when it goes into RRC-IDLE is known as DRX while the other one is known as CDRX (Continuous DRX). CDRX is used in RRC -Connected mode and it is configured by eNodeB through RRC connection re-configuration message.
The purpose of both DRX is same "save power" for the UE.

Answer 3

Hi Ankit,

As per ENB implementation, UE should not send any SR/BSR during DRX off duration. Even if it has data it should wait for the next available ON duration and then send the request to ENB.

Because during DRX off duration ENB will not listen for the PUCCH request, Then SR will not be received at the ENB.