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8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 3 Abbreviations | For the purposes of the present document, the following abbreviations apply: AACH Access Assignment CHannel AI Air Interface AoA Angle of Arrival ASCCH Assigned Secondary Control CHannel AVL Automatic Vehicle Location BER Bit Error rate BNCH Broadcast Network CHannel BS Base Station BSCH Broadcast Synchronization CHann... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 4 Executive Summary | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 4.1 General Overview | TG23 was formed as a joint EPT WG2/WG3 task group to perform the voluntary feasibility study work for AI enhancements for TETRA Release 2. Seven meetings were held between November 2000 and June 2001, with participation from at least ten different member organizations. Additionally, TETRA Release 2 user requirements in... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 4.2 Conclusions and Recommendation | The TETRA Release 2 AI enhancements options are divided into three categories based on the level of cost vs. benefit for the given option. The categories are phase 1, phase 2, and phase 3. It is recommended that TETRA Release 2 standardization work for the feasible options requiring standardization listed in clause 6 b... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5 Work Areas | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.1 General | During the enhancements analysis it was found that many of the enhancements could be grouped into "enhancement packages" based on their interdependence in producing a benefit(s). The work was divided accordingly into four different sub-areas based on the groupings, and to map to the TETRA Release 2 primary objectives. ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.1 General | This clause describes results of analysis and feasibility assessment of enhancements including consideration of C/I measurements, improved power control, measurement reporting, improved handover, frequency hopping, fractional loading and hierarchical cell structures. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.2 Improved Handover | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.2.1 Background | This clause of the present document has been prepared to advance suggestions for improving the existing handover mechanisms in TETRA. Handover has to be considered for an MS, which is idle, engaged in a circuit mode call or packet data session. Some parameters apply to only one state whereas others apply to an MS in ei... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.2.2 No Standard Changes | This clause looks at changes that could be made to improve the handover efficiency with no changes to the standard. The changes are operational and implementation. Some of these implementational aspects could be considered for annexes to EN 300 392-2 [1] or inclusion into the TIP process. Operational Changes Handover P... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.2.3 Minor Standard Changes | This clause looks at changes that could be made to improve the handover efficiency with minor changes to the standard. Downlink RSSI measurement Currently 10.3.1 defines the accuracy of RSS measurement to be +/-4 dB. Other clauses (23.7.3) hint at ways of sampling and measurement methodology but there is no absolute de... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.2.4 Major Standard Changes | This clause suggests improvements that will need non-trivial changes to the TETRA standard. The changes in the main involve new PDUs on the air interface and new procedures to use the signalling. Changes to PDUs and new PDUs will need additional research into any effect on loading of the MCCH, FACCH and SACCH of the se... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.3 Hierarchical Cell Structures | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.3.1 Introduction | Mobile users vary in speed, use and density. It is not unusual to find environments that range from very high traffic density hotspots to very sparsely distributed users. The following two examples show typical cases for mobile user profiles: • Low speed, high use and high density such as pedestrians in "hot spots". • ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.3.2 Macrocells vs. Microcells | The macro layer is a layer of large cells intended to satisfy coverage requirements with as few cells as possible. Macro base stations transmit high power, and their antennas are fitted on masts above average roof top level to achieve maximum coverage possible. On the other hand, microcells are small cells intended to ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.3.3 Requirements for Hierarchical Cell Structures | A few techniques can be employed to support hierarchical cell structures in TETRA. These techniques vary in complexity, flexibility and reliability. At the bottom end, the ‘priority cell’ feature can be used to distinguish microcells from macrocells. This will not require change to the standard but the flexibility and ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.4 Frequency Hopping and Fractional Loading | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.4.1 Introduction | Frequency Hopping (FH) is a technique used in mobile communication systems to minimize the effect of bad links. In this text, a bad link is a link with low C/I. This would result in a poor quality speech in the case of speech calls, and high BER in the case of data connections. By using proper frequency reuse, a good C... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.4.2 Benefits of Frequency Hopping | In Fast Fading Channels A fast fading channel is characterized by deep fades (as much as -30 dB) for short periods of time. The period that an MS remains in a deep fade depends on the speed of the user and the operating frequency. In some circumstances, this period can extend over a few TETRA frames. By using FH, an MS... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.2.4.3 The way forward | From the previous discussion, we can see significant benefits from Frequency Hopping. These benefits can be summarized as follows: • averages out the received interference over all hopping frequencies. • improves the quality of the signal in a fast fading channel by reducing the probability of having more than one TETR... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3 Improving terminal characteristics | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.1 General | This clause describes results of analysis and feasibility assessment of enhancements which affect terminal characteristics. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.2 Improved Battery Life - Energy Economy Mode | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.2.1 Introduction | One task of TG23 was to look for means of getting improved battery lifetime. One of the standard techniques for achieving this is to put the MS in a "sleep" state such that it is not monitoring control channel downlink frames continuously, reducing current consumption. The TETRA air interface standard supports signalli... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.2.2 Performance of First Generation Handsets | The current drain characteristics of two first generation handsets without energy economy mode implemented were measured for the idle mode state and are summarized in tables 1 and 2 under the column EG0. The lifetime figures using different levels of energy economy modes were modelled based on the measurements obtained... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.3 Improved Battery Life - Discontinuous Transmission | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.3.1 Introduction | One task of TG23 was to look for means of getting improved battery lifetime. One of the standard techniques for achieving this is to only transmit during a speech call when there is voice activity, thus reducing current consumption. This mode of operation, known as Discontinuous Transmission (DTX), is usually only appl... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.3.2 Performance of First Generation Handsets | This clause contains results of investigations into potential power savings through discontinuous transmission. Figure 1 depicts the power profiles of two first generation handsets, with the transmission period depicted. 0 2 4 6 8 10 12 14 16 0 10 20 30 40 50 Time (ms) Power (Watts) Handset A Handset B Transmit time Fi... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.3.3 Additional Standardization Work | There are two issues that need to be considered in the CODEC, speech quality and comfort noise generation during silent periods. DTX is likely to have an impact on the speech quality since it will introduce initial and final talk spurt clipping. The degree of degradation will depend on the effectiveness of the Voice Ac... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4 Improved Battery Life - Open and Closed Loop Power Control | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.1 General | Improved Battery Life - Open and Closed Loop Power Control looks at the potential battery lifetime savings that could be achieved by smaller power control steps and closed loop power control. A reduced lower limit for the dynamic range of power control was seen as not viable for battery life extension, however for othe... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.2 Methodology | It was assumed that a population of MSs is uniformly distributed over an idealized circular cell area with a fourth power loss law. The DC consumption was based on an MS being in simplex or duplex transmission 36 % and 8 % of the time respectively. For the open loop case the power saving afforded was evaluated using fo... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.3 Reduced Power Control Step Size (Open Loop) | This analysis suggests a saving of the order of 14,4 % in the limit, with an improvement of 12,5 % for a 1 dB-step size. The trade-off for step size is detailed in table 6. Table 6: Control step size and power savings in Open Loop power control Q_step dB Avg. Tx Power Saved Avg. DC Power Saved 4 9,9 % 4,6 % 3 15,8 % 7,... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.4 Increased Power Control Dynamic Range (Open Loop) | This has a saving of an additional 2-3 %, particularly in environments with significant slow fade. However the issues surrounding implementation of this are probably not worth surmounting for the available saving. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.5 Changing From Open to Closed Loop | There are two mechanisms giving a saving that have been evaluated separately. Link non-reciprocity may result is a significant improvement in Tx Power and DC power savings of up to 19-23 % in the limit depending upon the degree of link non-reciprocity. For a 1 dB step size the saving would be 17-20 %, showing a signifi... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.6 Closed Loop in a Fast Rayleigh Fade Environment | This analysis assumes that slow fade is tracked ideally by the power control system and investigates the power saving possible between closed loop power control at the current resolution and at smaller resolutions. The estimated saving is reproduced in table 9. Table 9: Control step size in Fast Fading Step size Total ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.4.7 Closed Loop Power Control Rate | To be reasonably effective at tracking downlink fades, a power control update rate would need to be of the order of 4 times per second, and 8 times a second for tracking loop non-reciprocity. However a significant benefit can be expected at lower update rates simply due to recovering the link margin associated with RSS... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.5 RF Characteristics | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.5.1 General | During the course of the study TG23 looked at other features which warrant further study. Some are terminal aspects but influence the system, especially in terms of interference. These are briefly listed below. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.3.5.2 Power mask | This could be useful for the manufacturer of MSs with smaller form factor and for use in pico cells. The lower power would help the system in its frequency re-use. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4 Optimization of frame structures & protocols | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1 Protocol Enhancements | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1.1 Introduction | This clause describes the results of an initial analysis and feasibility assessment of enhancements of the Air Interface protocols for TETRA Release 2. Together with a brief analysis of the following protocol layers - Physical, MAC, LLC and Layer 3 (SNDCP) including consideration of the optimization of frame structures... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1.2 The Physical layer | In order to ensure TETRA Release 1 compatibility the physical layer should remain unchanged in TETRA Release 2 to allow all TETRA mobiles and Base Stations to access the control channels. The Control uplink Burst (CB) and Normal Uplink Burst (NUB) should continue to be supported to ensure that a TETRA Release 1 MS can ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1.3 The MAC layer | An analysis of the MAC PDU header overheads and available length for payload data for TMA-SAP protocol is shown in the table 10. Table 10: MAC PDU format MAC PDU Header size (bits) Logical Channel Available payload size (bits) Uplink MAC-ACCESS 16 - 36 SCH/HU 76 - 56 MAC-END-HU 7 SCH/HU 85 SCH/F 245 - 231 MAC-DATA 23 -... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1.4 The LLC layer | Introduction The LLC layer may offer scope for optimization, by reducing the header size of either Basic Link or Advanced Link PDUs. A brief analysis into both types of link is covered in the following clauses. BASIC link As basic link PDUs require only 4 - 6 bits (without FCS) and 36-38 bits (with FCS) for the header ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.1.5 Layer 3 protocols | Introduction Examination of the lower levels of the protocol stack offers very little scope for enhancement. However within the layer 3 protocols there is a possibility that the size of some PDUs may lead to excessive fragmentation. This is covered in the following clauses. Transmission of Large PDUs As mentioned above... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.2 Reduced Speech Delay | In order to reduce the speech delay on the Air Interface a TCH could use all 18 frames in a multi-frame to transmit speech. However frame 18 is currently used to broadcast network information on the BNCH, for synchronization on the BSCH - downlink - and linearization on the CLCH - uplink, In addition, Frame 18 is also ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.4.3 Recommendations | The Physical Layer In order to maintain compatibility between TETRA Release 1 and TETRA Release 2 no changes are proposed to the physical layer of the Air Interface. The MAC Layer No enhancement changes to the MAC layer are proposed. The LLC Layer Basic Link No enhancement to the Basic Link protocol is proposed. Advanc... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5 User requirements implementation issues | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.1 General | This clause describes results of analysis and feasibility assessment of the enhancements of extended range and provision of location information. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2 TETRA LCS (Location Service) | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.1 Background | Location services are starting to emerge in cellular networks and cellular positioning is gaining increasing publicity both in media and telecommunications forums. The drivers of the positioning functionality have been both regulative and commercial. On the regulatory side the process was started in the USA, where the ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.2 Location dependent services (LDS) | Providing geographical co-ordinates does not have much value as such, but when related to some location dependent service (LDS) the information will have greater importance. The situation is totally different with the traditional GPS where positional co-ordinates, speed and heading are the main information that is util... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.3 Location issues related to TETRA | When considering implementation of location services to TETRA network there are some important aspects that must be considered. Firstly the viable location method(s) that could be implemented in the TETRA system have to be investigated. A second issue of importance is the additional signalling needed for those systems.... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.4 Location Accuracy and Update Rates for Emergency Service Users | A study undertaken for the UK Home Office on efficient transfer of AVL data over TETRA networks ascertained the requirements in table 15. Table 15: AVL data over TETRA requirements User Service Accuracy Update rate Comments Ambulance Service Better than 50 metres, preferably 10 metres Variable Most ambulance services n... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.5 Location methods | The key question of the TETRA location service is the method to be used. There are various methods that have been discussed within telecommunication arena. Since each of these methods will have both pros and cons, the methods with their key characteristics are presented here. Cell ID The simplest method for estimating ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.2.6 Summary | In the telecommunication standardization arena there are numerous different methods for location that have been dealt with. When making a decision on the method that should be accommodated in TETRA, following issues must be addressed: • Accuracy requirement • Implementation penalty of the Network • Implementation penal... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3 Extended Range Capability | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3.1 General | TETRA Release 1 has a limitation in range due to timing issues. For trunked mode the range is limited to about 58 km and for direct mode the limitation is even to be less. In some situations there is an operational need for an extended range. Requirement scenarios include aeronautical and maritime use, "linear cells" (... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3.2 Aeronautical | A typical situation for a longer range is aeronautical use over land or sea. In this situation the aeronautical mobile wants to have contact with other users on land. Propagation studies show that at 400 MHz a range of 200 km is feasible (based on free space path loss which applies instead of the modified Hata model). ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3.3 Linear cells | Coverage along a road or pipeline would also benefit from an extended range capability. In such a scenario, minimal traffic would be generated off the linear route. Characteristics Cell shape "linear" (directional base station antenna) Maximum BS-MS distance 120 km MS maximum speed 250 km/h (helicopter) Propagation env... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3.4 Large rural cells (Rural Telephony / Telemetry) | Another scenario for extended range would be for communication (primarily duplex) to fixed outstations and mobile stations in low density environments. Characteristics Cell shape "circular" Maximum BS-MS distance 80 km MS maximum speed 80 km/h Propagation environment Rural, possibly hilly Distribution of subscribers Un... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 5.5.3.5 Technical Means of Achieving Extended Range | The maximum radius of TETRA base station cells is a function of the guard band between the TDMA timeslots. The maximum transmission radius is defined such that each MS transmission arrives in its allocated slot at the BS. At the BS, a transmission from a remote MS in slot 1 can collide with a transmission from a local ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6 Feasible Options and Enhancements Phases | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.1 OPTIONS | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.1.1 Sub-area 1 | Improved Handover It is felt that handover could be improved by introducing the following options to the air interface standard (EN 300 392-2 [1]). 1) Define the RSS measurement methodology in the MS. This definition will impact on other areas of the present document, notably MS open loop power control and MS location ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.1.2 Sub-area 2 | The terminals sub-area determined that the most feasible options are: 1) Implement the energy economy mode of MS operation (clause 5.3.1) with guidelines on interaction with MM and neighbour cell measurement in the standard. Note this may interact with other clauses that also have some say in the RSS measurement (hando... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.1.3 Sub-area 3 | No options discussed at TG23 meetings - see clause 7.3 for details on unstudied options. ETSI ETSI TR 101 987 V1.1.1 (2001-08) 41 |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.1.4 Sub-area 4 | The user requirements sub-area determined that the most feasible options are: Location Information Cell ID (see clause 5.5.2.5) because it is a simple method that requires little standardization effort and no changes to the mobile stations, although the accuracy of the location is limited to the cell area. The standard... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2 Options by phase | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.1 Phase 1 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.1.1 Sub-area 1 options | Improved Handover It is recommended that Clause 6.1.2 options 1 to 8 (inclusive) should be incorporated in phase 1. This is because they will bring the largest benefits for the least amount of standardization work. It should be noted that several of these options are linked to power control of MSs and MS location servi... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.1.2 Sub-area 2 options | All options should be included in phase 1 as they bring benefits with small changes to the standards (Air Interface and Codec). There are no new PDUs or air interface signalling changes only changes in some values. The work mainly revolves around EN 300 392-2 [1], table 342, which has suggested changes from the "improv... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.1.3 Sub-area 3 options | None. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.1.4 Sub-area 4 options | Cell ID (see clause 5.5.2.5) because it is a simple method that requires little standardization effort and no changes to the mobile stations, although the accuracy of the location is limited to the cell area. The standardization effort would centre on procedural additions to the standard rather than any new PDUs - it i... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.2 Phase 2 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.2.1 Sub-area 1 options | Improved Handover It is felt that Clause 6.1.1 options 9 to 15 (inclusive) should be included into phase 2. This is because work in standardization will bring about benefits in consistent behaviour and flexibility in operation of handover. The working groups must consider the half-duplex calls (individual and group) an... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.2.2 Sub-area 2 options | None. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.2.3 Sub-area 3 options | None. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.2.4 Sub-area 4 options | Received Signal Strength (RSS) (see clause 5.5.2.5) is considered to be a phase 2 option because, although of variable accuracy by itself, when combined with Cell ID it could provide enhanced accuracy. Since its implementation would require co-ordination and signalling between base stations and hence also a moderate de... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.3 Phase 3 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.3.1 Sub-area 1 options | Frequency Hopping Two work streams have been identified as areas of research to determine the feasibility of Frequency Hopping in TETRA, these are: 1) Investigate solutions to surmount the Linearization issue, which seems to be a barrier to implementing Frequency Hopping in TETRA. 2) Evaluate the benefits of FH and com... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.3.2 Sub-area 2 options | None. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.3.3 Sub-area 3 options | None. |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.2.3.4 Sub-area 4 options | The timing advance method of achieving extended range (see clause 5.5.3.5) is considered to be a phase 3 option because it would require significant standardization effort with major impact on terminals and base stations (with backward compatibility implications) but would be more spectrally efficient than the every ot... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 6.3 Enhancements timeline | Enhancement timeline is proposed to be as defined in table 21. Table 21: Implementation Phases 2001 (Q3,Q4) 2002 2003 Phase 1 Phase 2 Phase 3 study work ETSI ETSI TR 101 987 V1.1.1 (2001-08) 44 |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7 Other options | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.1 General | Some other options to enhance system performance were considered. These fall into two categories: some of them were considered unfeasible and therefore dismissed at an early stage of TG23 work. The others were not considered or studied within TG23, but believed to be worthy of studying to determine their feasibility. T... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.2 Sub-area 1 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.2.1 Unfeasible options | These options were considered unfeasible at an early stage of TG23 work. Therefore, they were not pursued any further. These options are: • Downlink Power Control. NOTE 1: suggested that downlink power control could reduce system interference. However, implementation issues associated with ramping power up and down on ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.2.2 Unstudied options | Some techniques can be used to enhance system performance and improve system quality. Such techniques might have some air interface requirements in order to be implemented. These techniques are: 1) Smart antennas. 2) Underlay/Overlay. 3) Equalizers and the use of Time Selection Diversity. 4) Directed Retry. The impact ... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.3 Sub-area 2 | None |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.4 Sub-area 3 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.4.1 Unfeasible Options | Transmission of large segments by "Slot spanning" or "Slot Chaining" (see clause 5.4.1.4) was determined as unfeasible. The increased throughput was insufficient to justify further investigation. The retransmission of failed segments would further reduce the effective throughput on the Air Interface. ETSI ETSI TR 101 9... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.4.2 Unstudied options | The following options mentioned in the "Transmission of Large PDUs" clause above were not discussed within the TG23 forum: • Use of advanced Link for large PDUs; • Protocol Configuration for SNDCP. Implementation of an Advanced Link for large PDUs is a feasible option as it is permitted within the current Air Interface... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.5 Sub-area 4 | |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.5.1 Unfeasible options | These options were considered unfeasible in the TG23 work. Therefore, they were not pursued any further. These options are: Timing Advance / Round Trip Time (TA / RTT) (see clause 5.52.5) because these methods would be limited to a location accuracy of 1-2 km and would incur unjustifiable implementation costs in the TE... |
8e3767d8ae9467e9edbfd8b01e1e28b7 | 101 987 | 7.5.2 Unstudied options | None identified. ETSI ETSI TR 101 987 V1.1.1 (2001-08) 46 Annex A: Options vs. Requirements Matrix The following matrix has been used during the initial process of identifying options and mapping them to the requirements. It is included here for background information and should not be considered part of the report rec... |
1af665171ad5782d3c09f2faccdce1eb | 101 956 | 1 Scope | The present document describes the technical analysis made on new TCR standard definition in the frame of ETSI/ECSS standardization work, according to operators' needs. Operators' needs are summarized in annex B. The new standard definition is mainly based on Direct Sequence Spread Spectrum techniques (DS/SS). |
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