Content for TR 43.801 Word version: 12.0.0
0 Introduction
1 Scope
2 References
3 Definitions and abbreviations
4 Objectives
5 Common Assumptions for Candidate Evaluation
...
...
0 Introduction p. 5
VAMOS has been specified as a Rel-9 feature and was expected to theoretically double the voice capacity of GERAN per BTS transceiver. Capacity gains of VAMOS have however been seen from system level simulations to vary significantly depending on the frequency load of the network. In networks with relatively high frequency load the possible system capacity increase brought by VAMOS could thus result in degraded call quality.
Call quality in the network may rely upon factors which were not modelled/covered in the MUROS study, such as radio resource management and interference coordination/mitigation mechanisms. Hence it is desirable to explore standardization ways in these and/or other possible areas to optimize the call quality of VAMOS networks.
1 Scope p. 6
The present document contains the results from the 3GPP study item on VAMOS Enhancements. This includes study of the following aspects:
- Objectives of the study.
- Common assumptions for the evaluation of candidate techniques.
- Candidate techniques including those that utilize network synchronization, and further those that use inter-cell interference coordination/mitigation and inter-cell channel state sharing in and between BSS. A candidate technique will support frequency hopping.
- Evaluations of candidate techniques based on the objectives.
2 References p. 6
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2]
TR 41.001: "GSM Specification set".
→ to date, withdrawn by 3GPP
[3]
→ to date, withdrawn by 3GPP
TR 45.914: (V9.5.0) "Circuit switched voice capacity evolution for GSM/EDGE Radio Access Network (GERAN)".
[4]
TR 45.926: "Potential solutions for energy-saving for GSM/EDGE radio access BTS".
[5]
GP-111597: "Coordinated Channel Allocation for VAMOS", Huawei Technologies Co., Ltd., ZTE Corporation, 3GPP GERAN#52.
[6]
GP-100619: "VAMOS system performance optimization by a coordinated RRM method", China Mobile Com. Corporation, 3GPP GERAN#46.
[7]
GP-120598: "Aspects of synchronous interference", Telefon AB LM Ericsson, 3GPP GERAN#54.
[8]
GP-130995: "Link to System Modelling and Verification for ENHVAMOS (update of GP-130429)", Huawei Technologies Co., Ltd., 3GPP GERAN#60.
[9]
GP-081024: "L2S mapping method for power imbalanced MUROS update", Huawei Technologies Co., Ltd., 3GPP GERAN#39.
[10]
GP-140311: "Updated System Performance Evaluation for Coordinated Channel Allocation (update of GP-140116)", Huawei Technologies Co., Ltd, GERAN #62.
[11]
GP-120636: "Draft 3GPP TR 45.926 V0.7.0 on Solutions for GSM/EDGE BTS Energy Saving", SI Rapporteur, GERAN #54.
[12]
GP-130544: "Draft TR 43.801 Solutions on VAMOS Enhancements v0.4.1", SI Rapporteur, GERAN #58.
[13]
GP-100104: "System Performance Evaluation for Repeated SACCH and Shifted SACCH", Huawei Technologies Co., Ltd, GERAN #45.
[14]
TS 44.018: (V9.2.0): "Mobile radio interface layer 3 specification; Radio Resource Control (RRC) protocol".
[15]
GP-140116: "Updated System Performance Evaluation for Coordinated Channel Allocation (update of GP-130997)", Huawei Technologies Co., Ltd, GERAN #61.
3 Definitions and abbreviations p. 7
3.1 Definitions p. 7
For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.
3.2 Abbreviations p. 7
For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
MUROS
Multi-User Reusing One Slot
VAMOS
Voice services over Adaptive Multi-user Channels on One Slot
RRM
Radio Resource Management
4 Objectives p. 7
4.1 Performance Objectives p. 7
4.1.1 Improved Call quality p. 7
The ENHVAMOS candidate techniques will improve the call quality of both paired and non-paired mobiles in a VAMOS network.
4.2 Compatibility Objectives p. 7
4.2.1 Impacts to the Core Network p. 7
No implementation impacts will be required for the core network. Any increase of signalling load on the A interface should be avoided.
4.2.2 Impacts to the BSS p. 7
No implementation impacts will be required for the BTS and BSC hardware. Additional complexity in terms of processing power and memory should be kept to a minimum for the BSC.
4.2.3 Impacts to Mobile Stations p. 7
No implementation impacts will be required for mobile stations.
4.2.4 Impacts to Network Planning p. 8
The study takes into consideration the dependency of the gains of an ENHVAMOS candidate technique upon factors like frequency reuse, frequency hopping mode (i.e. baseband hopping or synthesized hopping), and level of air interface synchronization etc.
5 Common Assumptions for Candidate Evaluation p. 8
5.1 General p. 8
The common working assumptions for the performance evaluation of ENHVAMOS candidate techniques are aligned with subclause 5 of the MUROS TR [3], except those explicitly listed in the following subclauses.
5.2 Air Interface Synchronization p. 8
For a candidate technique which requires network synchronization as a precondition, the system level performance should be evaluated in synchronous network mode. Otherwise the system level performance should be evaluated in both synchronous network mode and asynchronous network mode.
A candidate technique should indicate the level of synchronization it relies on, e.g. frame-based or multiframe-based, and possibly the dependency of the gains on the synchronization accuracy.
5.3 Definition of Model for External Interferers for Link Level Evaluations in Synchronous Network Mode p. 8
The synchronous interferer scenarios defined in the MUROS TR [3] (i.e. MTS-1 and MTS-2) can be reused for the purpose of link-to-system mapping (see subclause 5.7).
5.4 Definition of Model for External Interferers for Link Level Evaluations in Asynchronous Network Mode p. 8
The asynchronous interferer scenarios defined in the MUROS TR [3] (i.e. MTS-3 and MTS-4) can be reused for the purpose of link-to-system mapping (see subclause 5.7).
5.5 Interference Measurement and Recording p. 8
5.5.1 Uplink Measurement p. 8
For the BTS the same measurement period as for the MS is assumed. RXQUAL and RXLEV are measured.
If a candidate technique utilizes interference measurements on the UL, then this will be realistically modelled.
5.5.2 Number of Reported Cells p. 8
The definition of the number of reported cells is 6.
The BA list will be modelled if it is used to determine reported cells.
If the BA list is adapted by a candidate technique then this will be modelled. The impact of such an adaptation on handover is expected to be seen in the speech quality.
5.5.3 Definition of Call Set-up Phase p. 9
The maximum call set-up phase is defined as 3 seconds.
5.5.4 BCCH Carrier Measurements p. 9
The BCCH carrier measurement will be modelled by re-using the approach defined in subclause 6.5.1.2, 6.5.2 and 6.5.3 of TR 45.926 for the MS in connected mode. Only CS services are assumed on the BCCH carrier.
The backoff used in simulations will be declared.
5.6 Network Configurations p. 9
5.6.1 Information Sharing at RRM Level p. 9
Three levels of information sharing are defined:
- Level 1, where no information sharing is applied.
- Level 2, where information sharing is applied only within the BSSs.
- Level 3, where information sharing is applied in and between the BSSs.
5.6.2 Simulation Scenarios p. 9
The reference case will be based on MUROS-1, MUROS-2 and MUROS-3 defined in the MUROS TR [3].
If a candidate technique relies on network synchronization, it will be evaluated against information sharing level 2 and level 3.
5.6.3 BSC Area and Inter-BSC Information Exchange p. 9
To model the BSC area one BSS-to-BSS border is defined. The number of cells next to the BSS-to-BSS border and the total number of simulated cells will be declared.
To model the information exchange between BSCs, an inter-BSC connection should be defined. This is done in a vendor specific way, but the assumptions on the inter-BSC connection will be declared. Such assumptions will cover parameters e.g. delay, bandwidth and reliability.
It is expected that the ENHVAMOS study as an output will give recommendation on the above mentioned parameters.
5.6.4 Impact on TCH FER due to Handover p. 9
The impact on traffic channel FER due to handover should be taken into account for both downlink and uplink, in a vendor specific way.
5.7 Link-to-System Mapping p. 9
Re-use of the L2S mappings that were generated during the MUROS study (see clause 5.7 of the MUROS TR [3]) is allowed.
In the case of network synchronization the following is taken into consideration:
- If dynamic TSC planning methods are utilized then impact from carrier and interferer TSC cross correlation combinations configured in system simulations will be modelled.
- Otherwise impact from every possible carrier and interferer TSC cross correlation combination will be modelled.
5.8 System Performance Evaluation Method p. 10
Two system performance evaluation methods are defined:
- To evaluate the system performance of an ENHVAMOS candidate technique in terms of capacity gains, the system performance evaluation method defined in clause 5.5 of the MUROS TR [3] is re-used.
-
To evaluate the system performance of an ENHVAMOS candidate technique in terms of call quality improvements:
- the system is first loaded with the usage of VAMOS but without the usage of the ENHVAMOS candidate technique until the minimum call quality performance is not any more ensured. This is treated as the reference case.
- the system is then loaded with the usage of both VAMOS and the ENHVAMOS candidate technique, and with the same amount of traffic as the above reference case.
- the system performance of the ENHVAMOS candidate technique in terms of call quality improvement is then calculated by the decrease of the median level in the CDF of average call FER.
5.9 Signalling Aspects p. 10
For any candidate technique the evaluation should include the impacts to the signalling loads over any affected interface between network elements. Such impacts should be taken into account when comparing candidate techniques.
