D. Vinayagam (AP - faculty, IFETCE, Anna university), R. Kurinjimalar, D. Srinivasan, “Performance evaluation of cross layer QoS scheduling for Long Term Evolution Network,” International Journal of Advanced Computer Research (IJACR) (ISSN (print): 2249-7277 ISSN (online): 2277-7970) Volume-2 Number-3 Issue-5 September-2012, Pg.75-83, Impact -1.863.
Performance evaluation of cross layer QoS scheduling for Long Term Evolution Network
D. Vinayagam, R. Kurinjimalar, D. Srinivasan
fulltext: http://www.theaccents.org/ijacr/papers/current_sep_2012/13.pdf
pages: 75 - 83
(abstract)
BIBLEX save it in notepad as .bib
@article{vinayagam2012performance,
title={Performance evaluation of cross layer QoS scheduling for Long Term Evolution Network},
author={Vinayagam, D and Kurinjimalar, R and Srinivasan, D},
journal={International Journal of Advanced Computer Research (ISSN (print): 2249-7277 ISSN (online): 2277-7970)},
volume={2},
number={5},
pages={75--83},
year={2012},
publisher={The accents publisher}
}
Towards 4g LTE (Long Term Evolution)
1.Support scalable bandwidths -1.4, 3.0, 5.0, 10.0 and 20.0 MHz
2. Peak data rate that scales with system bandwidth
Downlink (2 Ch MIMO) peak rate of 100 Mbps in 20 MHz channel
Uplink (single Ch Tx) peak rate of 50 Mbps in 20 MHz channel
3. Supported antenna configurations
Downlink: 4x2, 2x2, 1x2, 1x1
Uplink: 1x2, 1x1
4. Spectrum efficiency
Downlink: 3 to 4 x HSDPA Rel. 6
Uplink: 2 to 3 x HSUPA Rel. 6
5. Latency
C-plane: <50 – 100 ms to establish U-plane
U-plane: <10 ms from UE to server
6. Mobility
Optimized for low speeds (<15 km/hr)
High performance at speeds up to 120 km/hr
Maintain link at speeds up to 350 km/hr
7. Coverage
Full performance up to 5 km
Slight degradation 5 km – 30 km
Operation up to 100 km should not be precluded by standard
PACKET SCHEDULING ALGORITHMS
The packet scheduling algorithms normally classified into two categories:
Physical layer-channel quality information (PHY layer - CQI) based packet scheduling algorithm (Max C/I and RR (Round Robin)) and are designed only for single-service situation
Cross-layer based packet scheduling algorithm (PF (Proportional Fairness), M-LWDF (Modified Largest Weighted Delay First) and EXP-rule) which takes into consideration both PHY-layer CQI as well as data link layer buffer queue information.
They satisfy the principle of multi-service directly
M-LWDF (Modified Largest Weighted Delay First) and EXP-rule, considering time delay for better throughput performance can be achieved, but its packet loss rate performance is still insufficient.
EXP/PF scheduling scheme is to schedule the stream service and best-effort service with EXP-rule and PF-rule respectively.
QoS and Radio Bearer
The Bearer class models the dedicated radio bearer. When a downlink (uplink) flow starts, it activates a dedicated radio bearer between eNodeB and UE (UE and eNodeB) and vice versa
Types of bearer:
(1) Guaranteed bit rate (GBR) which is a permanent bearer and
(2) Non-guaranteed bit rate (non-GBR) which is an IP connectivity bearer.
GBR and non-GBR bearers are associated with different bearer-level QoS parameters which is called QoS Class Identifier (QCI).
The QCI is a scalar denoting a set of transport characteristics (bearer with/without guaranteed bit rate, priority, packet delay budget, packet error loss rate)
QCI used to infer nodes specific parameters that control packet forwarding treatment (e.g., scheduling weights, admission thresholds, queue management thresholds, link-layer protocol configuration, etc.
CROSS LAYERING
A number of (physical and medium access layer) parameters are jointly controlled and functioned with higher layer functions like resource allocation, admission control and routing. Optimization method mainly involving PHY and MAC to manage the system resources adaptively
Channel quality indicators are message signal that are sent on a mobile communication system that provide the remote connection (e.g. ENB -ENodeB) with channel quality information.
Channel quality information ---- combination of carrier level received signal strength indication (RSSI) and bit error rate (BER)
by Vinayagam D
Cross Layer Concept in LTE scheduling
The eNodeB creates a list of downlink flows having packets to transmit
MAC queue length and CQI feedbacks are stored for corresponding to each flow.
Scheduling strategy, the chosen metric is computed for each flow
The eNodeB assigns each sub-channel to the users in the flow list that presents the highest metric
For each scheduled flow, the eNodeB computes the size of transport block, i.e., the quota of data that will be transmitted at the MAC layer during the current TTI.
Cross layer QoS downlink scheduler
Design principle of scheduler
Performance evaluation of cross layer QoS scheduling for Long Term Evolution Network
D. Vinayagam, R. Kurinjimalar, D. Srinivasan
fulltext: http://www.theaccents.org/ijacr/papers/current_sep_2012/13.pdf
pages: 75 - 83
(abstract)
BIBLEX save it in notepad as .bib
@article{vinayagam2012performance,
title={Performance evaluation of cross layer QoS scheduling for Long Term Evolution Network},
author={Vinayagam, D and Kurinjimalar, R and Srinivasan, D},
journal={International Journal of Advanced Computer Research (ISSN (print): 2249-7277 ISSN (online): 2277-7970)},
volume={2},
number={5},
pages={75--83},
year={2012},
publisher={The accents publisher}
}
Cite
Copy and paste a formatted citation or use one of the links to import into a bibliography manager.
MLA
Vinayagam,
D., R. Kurinjimalar, and D. Srinivasan. "Performance evaluation of
cross layer QoS scheduling for Long Term Evolution Network." International Journal of Advanced Computer Research (ISSN (print): 2249-7277 ISSN (online): 2277-7970) 2 (2012).
|
APA
Vinayagam,
D., Kurinjimalar, R., & Srinivasan, D. (2012). Performance
evaluation of cross layer QoS scheduling for Long Term Evolution
Network. International Journal of Advanced Computer Research (ISSN (print): 2249-7277 ISSN (online): 2277-7970), 2.
|
Chicago
Vinayagam,
D., R. Kurinjimalar, and D. Srinivasan. "Performance evaluation of
cross layer QoS scheduling for Long Term Evolution Network." International Journal of Advanced Computer Research (ISSN (print): 2249-7277 ISSN (online): 2277-7970) 2 (2012).
|
Towards 4g LTE (Long Term Evolution)
- LTE - evolution of mobile broadband technology that will deliver users the benefits of faster data speeds and new services by creating a new radio access technology that’s optimized for IP-based traffic and offers operators a simple upgrade path from 3G networks.
- LTE is the name of the 4G efforts being undertaken in Europe.
- LTE is the result of ongoing work by the 3rd Generation Partnership Project (3GPP), a collaborative group of international standards organizations and mobile-technology companies.
- 3GPP(3rd Generation Partnership Project), IEEE and 3GPP2 are three major standard development groups that are in tight competition to satisfy 4th generation requirements.
1.Support scalable bandwidths -1.4, 3.0, 5.0, 10.0 and 20.0 MHz
2. Peak data rate that scales with system bandwidth
Downlink (2 Ch MIMO) peak rate of 100 Mbps in 20 MHz channel
Uplink (single Ch Tx) peak rate of 50 Mbps in 20 MHz channel
3. Supported antenna configurations
Downlink: 4x2, 2x2, 1x2, 1x1
Uplink: 1x2, 1x1
4. Spectrum efficiency
Downlink: 3 to 4 x HSDPA Rel. 6
Uplink: 2 to 3 x HSUPA Rel. 6
5. Latency
C-plane: <50 – 100 ms to establish U-plane
U-plane: <10 ms from UE to server
6. Mobility
Optimized for low speeds (<15 km/hr)
High performance at speeds up to 120 km/hr
Maintain link at speeds up to 350 km/hr
7. Coverage
Full performance up to 5 km
Slight degradation 5 km – 30 km
Operation up to 100 km should not be precluded by standard
PACKET SCHEDULING ALGORITHMS
The packet scheduling algorithms normally classified into two categories:
Physical layer-channel quality information (PHY layer - CQI) based packet scheduling algorithm (Max C/I and RR (Round Robin)) and are designed only for single-service situation
Cross-layer based packet scheduling algorithm (PF (Proportional Fairness), M-LWDF (Modified Largest Weighted Delay First) and EXP-rule) which takes into consideration both PHY-layer CQI as well as data link layer buffer queue information.
They satisfy the principle of multi-service directly
M-LWDF (Modified Largest Weighted Delay First) and EXP-rule, considering time delay for better throughput performance can be achieved, but its packet loss rate performance is still insufficient.
EXP/PF scheduling scheme is to schedule the stream service and best-effort service with EXP-rule and PF-rule respectively.
QoS and Radio Bearer
The Bearer class models the dedicated radio bearer. When a downlink (uplink) flow starts, it activates a dedicated radio bearer between eNodeB and UE (UE and eNodeB) and vice versa
Types of bearer:
(1) Guaranteed bit rate (GBR) which is a permanent bearer and
(2) Non-guaranteed bit rate (non-GBR) which is an IP connectivity bearer.
GBR and non-GBR bearers are associated with different bearer-level QoS parameters which is called QoS Class Identifier (QCI).
The QCI is a scalar denoting a set of transport characteristics (bearer with/without guaranteed bit rate, priority, packet delay budget, packet error loss rate)
QCI used to infer nodes specific parameters that control packet forwarding treatment (e.g., scheduling weights, admission thresholds, queue management thresholds, link-layer protocol configuration, etc.
CROSS LAYERING
A number of (physical and medium access layer) parameters are jointly controlled and functioned with higher layer functions like resource allocation, admission control and routing. Optimization method mainly involving PHY and MAC to manage the system resources adaptively
Channel quality indicators are message signal that are sent on a mobile communication system that provide the remote connection (e.g. ENB -ENodeB) with channel quality information.
Channel quality information ---- combination of carrier level received signal strength indication (RSSI) and bit error rate (BER)
The Channel quality indicator (CQI) of the definition
- A combination of modulation scheme and transport block size corresponds to a CQI index
- Each PDSCH transport block ((modulation scheme + transport block size) CQI index)
- Block occupying a group of downlink physical resource blocks CSI reference resource, received with a transport block error probability (< 0.1).
- Highest CQI index between 1 and 15 condition, or CQI index 0 if CQI index 1 does not satisfy the condition,
- In the frequency domain, the CSI reference resource is defined by the group of downlink physical resource blocks corresponding to the band to which the derived CQI value relates.
- For periodic CSI reporting, it is an element of the CSI subframe set linked to the periodic CSI report when that UE is configured with CSI subframe sets.
- An OFDMA frame is divided into K sub channels in the frequency domain and T symbols in the time domain.
- In each OFDMA frame there are T × K slots and each UE may be allocated one or more such slots according to its application requirements.
- The slot on the kth subchannel at the tth symbol denoted as (kth, tth) slot.
- The CQI of the whole frame is perfectly known at the eNodeB through messages from UEs
Cross Layer Concept in LTE scheduling
The eNodeB creates a list of downlink flows having packets to transmit
MAC queue length and CQI feedbacks are stored for corresponding to each flow.
Scheduling strategy, the chosen metric is computed for each flow
The eNodeB assigns each sub-channel to the users in the flow list that presents the highest metric
For each scheduled flow, the eNodeB computes the size of transport block, i.e., the quota of data that will be transmitted at the MAC layer during the current TTI.
Cross layer QoS downlink scheduler
Design principle of scheduler
- Packet belonging to same SDF but to different UEs are queued in different logical queues.
- Packets in the queue are in the order of arrival time
- Packet are reordered based on earliest delay deadlines sensitive Real Time SDFs
- Only HOL packet PHOL in each queue is consider in each scheduling decision
