Recently, millimeter-wave (mmWave) communications have received great attention due to the availability of large spectrum resources. Nevertheless, their impact on TCP performance has been overlooked, which is observed that the said TCP performance collapse occurs owing to the significant difference in signal quality between LOS and NLOS links. We propose a novel TCP design for mmWave communications, a mmWave performance enhancing proxy (mmPEP), enabling not only to overcome TCP performance collapse but also exploit the properties of mmWave channels. The base station installs the TCP proxy to operate the two functionalities called Ack management and batch retransmission. Specifically, the proxy sends the said early-Ack to the server not to decrease its sending rate even in the NLOS status. In addition, when a packet-loss is detected, the proxy retransmits not only lost packets but also the certain number of the following packets expected to be lost too. It is verified by ns-3 simulation that compared with benchmark, mmPEP enhances the end-to-end rate and packet delivery ratio by maintaining high sending rate with decreasing the loss recovery time.
|Title of host publication||2017 IEEE International Symposium on Personal, Indoor and Mobile Radio Communications|
|Subtitle of host publication||Engaged Citizens and their New Smart Worlds, PIMRC 2017 - Conference Proceedings|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||5|
|Publication status||Published - 2018 Feb 14|
|Event||28th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2017 - Montreal, Canada|
Duration: 2017 Oct 8 → 2017 Oct 13
|Name||IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC|
|Other||28th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2017|
|Period||17/10/8 → 17/10/13|
Bibliographical noteFunding Information:
(a) Rate (b) Delivery ratio Fig. 6. Average rate and delivery ratio with different TCP proxy implementations under long LOS regime where NLOS is changed from 1 to 20 seconds but LOS duration is fixed to 100 seconds. The maximum sending rate and RWIN size are 100 Mbps and 6 MB, respectively. because a retransmission is triggered by not a base ACKNOWLEDGEMENT station but a server, resulting in less trials of packet This work was supported by ’The Cross-Ministry retransmission than PEP and mmPEP. Nevertheless, the Giga KOREA Project’ grant funded by the Korea gov- conventional TCP is not an efficient scheme in mmWave ernment (MSIT) (No.GK17S0400, Research and Devel- communication because its rate is quite low shown in opment of Open 5G Reference Model) Fig. 5(a). REFERENCES Fig. 6 shows the rate and delivery ratio of different TCP implementations under long LOS regime where LOS period is relatively larger than NLOS. Similar tendencies in Fig. 5 are observed but one distinct point is the significant rate gap between PEP and mmPEP when NLOS period becomes larger than 10 seconds. Under NLOS status, the mobile receives out-of-order packets that cannot be delivered to the application layer until the reception of in-order ones. As NLOS lasts more than 10 seconds, some packets should be discarded in PEP be- cause there is no available cache space in the mobile to save the next arrived packets. This delays loss-recovery and resulting in more retransmissions by a timer. On the other hand, the batch retransmission of mmPEP allows to deliver packets without the corresponding duplicated ACKs, making the sequence of in-order packet faster. This difference leads to the gap of delivery ratios when NLOS becomes longer than 10 seconds.
© 2017 IEEE.
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering