TTI bundling has been recently introduced as a feature of LTE. Rel. 8 to improve the uplink coverage. In TTI bundling, a VoIP packet is transmitted as a single. TTI Bundling optimizes the uplink (cell edge) coverage for services like VoLTE. For services such as VoIP, the packet size is small and the. TTI Bundling in FDD and TD-LTE Abstract TTI Bundling has been introduced in FDD Alternative Approach The alternative to TTI bundling is.

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Winnie Lee August 4, at 4: Eric November 29, at 8: Latency is also reduced as no waiting time is required between the retransmissions.

This approach can also reduce the delay in the HARQ process compared to transmissions of the redundancy versions separated in time using the normal approach. But the real implementation and optimization may not as easy as it sound. Now you may have another question.

Newer Post Older Post Home. Should it be always like this i. The process as shown in Figure 3 is typically triggered by UE informing the eNB about its power limitations at the present state. The reciever bnudling combine the previously recieved erroneous data with newly attempted data by the sender.

TTI Bundling in FDD and TD-LTE

But I haven’t seen any case in which this is enabled in live network, at least as of now Aug, There is one drawback however, that it can result in delay and too much control overhead in case of poor radio conditions if the sender has to attempt many transmissions. The purpose of TTI Bundling is to improve cell edge coverage and in-house reception for voice. Then Why we need this kind of method? Vicky January 15, at Sekhar joined Award Solutions inand has over 16 years of experience in wireless telecommunication industry with mobile cellular, digital communications technologies.


How LTE Stuff Works?: TTI Bundling

The channel coding used in LTE enables easy generation of the multiple redundancy versions from which the transmissions in the TTI bundle are generated. Or its just implementation difference. This triggers the eNB to transmit the various redundancy versions of the same transport block in consecutive bundlihg or TTIs giving rise to the name TTI bundling. Adnan Basir April 17, at 2: DJ May 29, at 3: What would be the advantages and drawbacks of TTI bundling compared to this other solution if it is possible to implement?

This way bunrling chances of successfully decoding the bits improve every time.

LTE TTI Bundling

Overview of TTI Bundling. In addition, since we are transmitting many small transport blocks, the chances of interpreting a NACK as a ACK also increases proportionately with the increase in the RLC segmentation size. On the other hand, sender will send the same data again but this time, bundlingg different set of coded bits.


This will repeat as long as the receiver is not able to decode the bundllng. According to this statement, the PHICH timing for all the case illustrated above the answer is same as follows. When the base station detects that the mobile can’t increase it’s transmission power and reception is getting worse it can instruct the device to activate TTI bundling and send the same packet but with different error detection and correction bits in 2, 3 or tyi 4 consecutive transmit time intervals.

Rachel Johnson October 13, at Check the following figure to understand the concept of TTI. Why are the durations of the TTIs all common, or equal?

TTI Bundling in FDD and TD-LTE – Sekhar – Expert Opinion – LTE University

Therefore, in a case where the communication is for time critical communication and UE is in the area of poor coverage e. One drawback of this method is the potential overhead increase due to RLC segmentation due to multiple RLC headers needed.

Combined processing of the redundant transmissions over multiple subframes leads to a better probability of detection of the transport block. There must be some technical reason why they are not varied.