1. Introduction
2. Scheduling for VoIP Services in E-UTRA Uplink
2.1. Conventional Dynamic Scheduling
2.2. Original Persistent Scheduling
2.3. A Proposed Scheduling Scheme
2.3.1. Concept of the Proposed Scheduling
Number | 1st pairing user's | 2nd pairing user's | Status |
---|---|---|---|
ACK channel | ACK channel | ||
1 | ACK | ACK | Maintaining |
2 | ACK | NACK | Changing |
3 | NACK | ACK | Changing |
4 | NACK | NACK | Maintaining |
2.3.2. User Pairing Method
2.3.3. Description of Overall Operation for a Proposed Scheduling Scheme
2.3.4. Discussion on the Control Channel Signaling Overhead
2.3.5. Power Control and Interference over Thermal in Uplink
3. VoIP Services over E-UTRA Uplink
3.1. The Properties of VoIP Services
3.1.1. Traffic Model and Protocol
3.1.2. Definition of VoIP Capacity
3.1.3. End-to-End Delay Latency for QoS Support
3.2. System-Level Simulation Setup
3.2.1. Physical Layer in E-UTRA Uplink
3.2.2. Simulation Environments
Parameter | Assumption |
---|---|
Source traffic packet overhead | AMR 12.2 kbps, |
VAF = 0.5, 2-state Markov, | |
ROHC 4 bytes [IETF RFC 3059] | |
Cellular layout | Hexagonal grid, 19 sites, 3 sectors |
(eNB-to-eNB 0.5 km) | |
Carrier frequency 2 GHz | |
System bandwidth | 5 MHz |
Propagation loss | Path loss = −128.1–37.6*log(R) |
Shadowing model | Log normal Std. dev. 8 dB, |
[Hata model] | |
User speed | 3 km/h |
Antenna gain | Node B 14 dB/UE 0 dB |
Penetration loss | −20 dB |
User Tx. Max. power | 24 dBm |
Fading model | Typical urban (TU) |
Thermal noise density | −174 dBm/Hz |
Number Rx ant. | 2 |
Retransmission | No RLC retransmission (No ARQ), |
sync. HARQ (max. retrial = 4), | |
HARQ process number = 8, | |
chase-combining | |
Power control | 50 Hz (sounding RS-based closed-loop method) |
Scheduling | Persistent scheduling with a resource sharing using user pairing, |
(repeated pattern period = 20 milliseconds) | |
MCS level | QPSK, 0.55 coding rate, |
talk-spurt period (2 RBs assign); | |
silent period (1 RB assign) | |
Link curve mapping | Effective SIR method (ESM) |
Link curve TTI | 1 millisecond |
Considered overheads | 29%(pilot and control overheads) |
2 long blocks for DM RS | |
4 RBs for control signals |
4. VoIP Capacity Evaluation
Capacity for | IoT [dB] | |
---|---|---|
VoIP services | ||
Original persistent scheme | 168 | 3 |
Proposed (random pairing) | 188 | 3.2 |
Proposed (best pairing) | 200 | 3.3 |
HSUPA (Release'6) | 70 | 3 |