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7323b7a140bcb2fd812315fde85112a7 | 102 277 | 5.5.4.2 Inter-frequency handover | Inter-frequency handover may typically occur in the following situations: • handover between spots to which different number of carriers have been allocated, e.g. due to different capacity requirements (hot-spot scenarios); • handover between spots of different overlapping orthogonal spot layers using different carrier... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 5.5.4.2.1 Dual-receiver | For a UE with receiver diversity, there is a possibility for one of the receiver branches to temporarily be reallocated from diversity reception and instead carry out reception on a different carrier, i.e. UE implements capability for simultaneous reception on distinct carriers. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 5.5.4.2.2 Slotted downlink transmission | With slotted downlink transmission, it is possible for a single-receiver UE to carry out measurements on other frequencies without affecting the ordinary data flow. When in slotted mode, the information normally transmitted during a 10 ms frame is compressed in time, either by code puncturing or by reducing the spreadi... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 5.5.5 UE energy saving optimization | Downlink slotted transmission can be used to reduce the average power consumption of UE, enabling the receiver to stay active for only a fraction of the time. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 5.5.6 Support of TDD | For further release. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6 Performance requirements | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.1 Test environment support | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.1.1 Satellite environment | UEs operate in either LOS or NLOS propagation conditions, i.e. either Rice or Rayleigh propagation channel. Path blockage can be induced by heavy shadowing from hills, tress, bridges and buildings. The car body (vehicular UE configuration) and the head of the user (handset UE configuration) can also have a non-negligib... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.1.2 Intermediate Module Repeater environment (IMR) | When UEs are on view of IMRs only (no view of the satellite signal), radio environment is terrestrial, i.e. propagation conditions apply as they are specified by 3GPP standards. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.1.3 Combined satellite and transparent IMR environment | When UEs are on view of both transparent IMRs and satellite signals, transparent IMRs introduce artificial multi-paths. The satellite and transparent IMR paths are to be added in the rake receiver fingers set. Satin project proposed propagation models that apply to combined satellite and IMR environment (see [33] and [... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.1.4 Aeronautical environment | Aeronautical environment is derived from [47], for a speed of 800 km/h. Table 6.7: Channel model; Aeronautical; 800 km/h Tap number Relative delay (ns) Average power (dB) Rice factor (dB) Doppler spectrum 1 0 0 14 Rice 2 11 500 -18 - |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2 Expected performances | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.1 Summary of test measurement services | The reference measurement channel for the 5 test services is summarized hereafter. Detailed description is given in annex A. Table 6.8: Reference measurement channels Parameter FACH for MTCH Unit Information bit rate 8 64 128 256 384 kbps Physical channel 15 120 240 480 480 ksps Spreading factor 256 32 16 8 4 - Repetit... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2 FACH demodulation requirements | Link level simulations have been run for the test environments and services described above in order to specify the FACH receiver performance requirements. The tables in next clauses include margin in order to take into account effects that are not modelled in simulations (imperfect channel estimation and path search, ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.1 Demodulation in static conditions | Table 6.11: FACH parameters in static propagation conditions Parameter Unit Phase reference P-CPICH oc or I Iˆ dB -1 oc I dBm/3,84 MHz -60 Table 6.12: FACH requirements in static propagation conditions Data rate or c I E CCPCH S _ − t b N E 8 kbps -19,6 dB 6,3 dB 64 kbps -12,8 dB 4 dB 128 kbps -10,3 dB 3,4 dB 256 kbps ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.2 Demodulation in ITU Channel model A conditions | The average or c I E CCPCH S _ − power ratio is specified for 2 UE locations: 20 % around spot centre and spot borders. Empty compartments mean the service is not reachable (situations suffering from too high adjacent-spot interference). ETSI ETSI TR 102 277 V1.2.1 (2007-02) 39 Table 6.13: FACH parameters in ITU channe... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.3 Demodulation in ITU Channel model B conditions | The average or c I E CCPCH S _ − power ratio is specified for 2 UE locations: 20 % around spot centre and spot borders. Empty compartments mean the service is not reachable (situations suffering from too high inter-spot interference). Table 6.15: FACH parameters in ITU channel model B conditions Parameter Unit Test 1 T... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.4 Demodulation in ITU Channel model C conditions | The average or c I E CCPCH S _ − power ratio is specified for 2 UE locations: 20 % around spot centre and spot borders. Empty compartments mean the service is not reachable (situations suffering from too high inter-spot interference). Table 6.17: FACH parameters in ITU channel model C conditions Parameter Unit Test 1 T... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.5 Demodulation in IMR environment conditions | FACH parameters for other cell interference are specified as reference [11]. Table 6.19: FACH requirements in IMR conditions Case 1 Case 2 Case 3 Data rate or c I E CCPCH S _ − t b N E Data rate or c I E CCPCH S _ − t b N E Data rate or c I E CCPCH S _ − t b N E 8 kbps -18,5 dB 17 dB 8 kbps -9,4 dB 13,1 dB 8 kbps -11,7... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.2.8 Demodulation in aeronautical environment | The requirements hereafter are applicable to a velocity of 800 km/h. The average or c I E CCPCH S _ − power ratio is specified for 2 UE locations: 20 % around spot centre and spot borders. Table 6.24: FACH parameters in ITU channel model C conditions Parameter Unit Test 1 Test 2 Phase reference P-CPICH oc or I Iˆ dB 9 ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3 Demodulation requirements synthesis | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.1 Fast fading propagation link margin | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.1.1 Satellite signal LOS view | In case UE is in ITU satellite models with LOS view of the satellite signal, simulation results show required propagation link margin is homogeneous all the test services. ETSI ETSI TR 102 277 V1.2.1 (2007-02) 44 Table 6.26: Maximum Propagation Link Margin; LOS ITU models Service type Downlink ITU Model A (rural) 2,1 d... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.1.2 Satellite signal NLOS view | When UEs are not in LOS view of the satellite signal, the required link margin becomes more critical, particularly for UEs at low speed (3 km/h), and is test service data rate dependent. Link margins are defined for two types of system deployment: satellite only (NLOS) and combined satellite/transparent IMRs. Table 6.2... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.1.3 Shadowing margin | Shadowing margin (trees, etc.) varies according to coverage area elevation. Shadowing margins in Europe, at 2,2 GHz, are given in the table 6.28: Table 6.28: Shadowing margin versus elevation UE Elevation Margin (dB) 10° 30,1dB 15° 19,8 dB 20° 14,7 dB 25° 11,7 dB 30° 9,6 dB 35° 8,2 dB 40° 7,1 dB 50° 5,5 dB |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.2 Increasing interleaving depth | Required Eb/Nt, and thus average or c I E CCPCH S _ − power ratio, can be decreased by increasing interleaving depth. One drawback of increasing interleaving depth is that this requires increasing UE memory size for buffering frames. This could be sensible for high data rate services (256 or 384 kbps). ETSI ETSI TR 102... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.3 Spatial diversity | Reception quality can be improved with two kinds of spatial diversity: UE antenna diversity and satellite diversity. NOTE: Satellite antenna diversity is not considered for satellite complexity reasons. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.3.1 UE antenna diversity | UE may be equipped with two reception antennas. Simulation results show a reduction of the required link margin regarding the propagation channel as depicted in table 6.30. Table 6.30: Link margin reduction; UE antenna diversity Propagation channel Link margin reduction AWGN 3 Case 1, S-case 1 6,5 Case 2, S-case 2 5,8 ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.3.3.2 Satellite diversity | Satellite diversity can be provided when the system is built with several satellites. This is an alternative to IMRs deployment for solving: • path blockage problem inherent to satellite systems; • propagation margin reduction. UEs receive simultaneously the same service from several satellites. Satellite diversity tak... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.2.4 Acquisition efficiency | Performance of initial spot synchronization was evaluated for several radio environments (see [35] and [36]). They are resumed hereafter. ETSI ETSI TR 102 277 V1.2.1 (2007-02) 47 1,E-03 1,E-02 1,E-01 1,E+00 False acquisition probability AWGN Rayleigh - 50 km/h Rice 5dB - 50 km/h Rice 15dB - 50 km/h VehicularMP - 50 km/... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.3 Satellite transmitter characteristics | Satellite transmission in the downlink MSS band is constrained by necessity to limit interference to terrestrial UMTS. It is assumed that the main constraint will be due to the protection of the reception by IMT-2000 UEs, in the lower adjacent terrestrial channel. ETSI ETSI TR 102 277 V1.2.1 (2007-02) 49 For a 74 dBW s... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.4 UE receiver characteristics | If terrestrial 3GPP UE are to be operated then their radio implementation must be upgraded for frequency agility to MSS bands. The UE RF performances are: Table 6.32: UE RF performance Receive frequency (MHz) 2 170 to 2 200 MHz UE type Handset Handheld Others Receive polarization Linear Circular Circular Noise figure 4... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 6.5 IMR transmitter characteristics | Table 6.33: IMR power characteristics Coverage area (°) Up to 360° (i.e. 120° per sector) IMR classes Wide area repeaters for macro-cell application Medium range repeaters for micro-cell Local area repeaters for pico-cell Assumed height of IMRs (m) 30 6 6 Maximum output power (dBm) 43 30 24 Maximum Antenna gain (Tx) (d... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7 System performances | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1 Link budgets | Link budgets are evaluated with the following assumptions: • GEO constellation (satellite altitude ~ 36 000 km thus free space loss close to 192 dB); • an average UE elevation of 30°, in rural areas; • UE located at spot border/End Of Coverage (EOC). This means the worst case to be compared to centre spot where higher ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1.1 Audio service 8 kbps | Table 7.1: Link budget; Audio 8 kbps FORWARD LINK BUDGET Handset Handheld Vehicular Transportable Handset Handheld Vehicular Satellite Location °E 10 10 Orbital Height Km 35786 35786 Unique Scrambling code no no no no no no no Center spot no no no no YES YES YES Calculation of interference from spot n+2 yes yes yes yes... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1.2 Data service 64 kbps | Table 7.2: Link budget; Data 64 kbps FORWARD LINK BUDGET Handset Handheld Vehicular Transportable Handset Handheld Vehicular Satellite Location °E 10 10 Orbital Height Km 35786 35786 Unique Scrambling code no no no no no no no Center spot no no no no YES YES YES Calculation of interference from spot n+2 yes yes yes yes... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1.3 Data service 128 kbps | Table 7.3: Link budget; Data 128 kbps FORWARD LINK BUDGET Handset Handheld Vehicular Transportable Handset Handheld Vehicular Satellite Location °E 10 10 Orbital Height Km 35786 35786 Unique Scrambling code no no no no no no no Center spot no no no no YES YES YES Calculation of interference from spot n+2 yes yes yes ye... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1.4 Data service 256 kbps | Table 7.4: Link budget; Data 256 kbps FORWARD LINK BUDGET Handset Handheld Vehicular Transportable Handset Handheld Vehicular Satellite Location °E 10 10 Orbital Height Km 35786 35786 Unique Scrambling code no no no no no no no Center spot no no no no YES YES YES Calculation of interference from spot n+2 yes yes yes ye... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.1.5 Data service 384 kbps | Table 7.5: Link budget; Data 384 kbps FORWARD LINK BUDGET Handset Handheld Vehicular Transportable Handset Handheld Vehicular Satellite Location °E 10 10 Orbital Height Km 35786 35786 Unique Scrambling code no no no no no no no Center spot no no no no YES YES YES Calculation of interference from spot n+2 yes yes yes ye... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2 System capacity | System capacity is summarized for at spot EOC as well as spot center for an exemplary satellite that provides 71 dBW at EOC. System capacity is also given for rural environment without margin for shadowing, i.e. constant LOS view of the satellite. This covers, among others, aeronautical UE configuration system capacity... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2.1 Orthogonality factor | An important point to note is the degradation of the orthogonality factor in presence of IMRs. In effect, for satellite only propagation channels, due to the low level of multipath components to be compared to the main path (see propagation channels in clause 6.1), the orthogonality factor is well preserve. This is tru... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2.2 Rural environment with shadowing | Table 7.8: System capacity; Rural with shadowing EOC Center spot Capacity/ carrier/ spot Nb codes/ spot/ carrier Link margin Capacity/ carrier/ spot Nb codes/ spot/ carrier Link margin (kbps) dB (kbps) dB Handset 8 kbps 352 88 9,6 872 218 9,6 64 kbps 512 8 9,7 1 280 20 9,6 128 kbps 640 5 9,4 1 536 12 9,4 256 kbps 768 3... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2.3 Rural environment with constant LOS view of the satellite | Link margin is decreased to 2,1 dB which is the margin required to cover UE demodulation performance degradation due to mobility in rural LOS conditions (ITU A LOS). Table 7.9: System capacity; Rural LOS EOC Center spot Capacity/ carrier/ spot Nb codes/ spot/ carrier Link margin Capacity/ carrier/ spot Nb codes/ spot/ ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2.4 Combined satellite and IMR environment | IMRs deployment allow to reduce the path blockage situations in urban environments (buildings, etc.), at the expense of capacity per carrier due to the loss of orthogonality coming from high level of multi-paths components in terrestrial propagation environment and due to the limited number of fingers of the UE Rake re... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 7.2.5 Hierarchical services structure | At this moment, it is recommended to structure broadcast services hierarchically: high priority data is mapped to low data rate channels (for example: 8 kbps or 64 kbps) while low priority data is mapped to high data rate channel. An illustrative example is: textual essential data sent over 8 kbps channel, images sent ... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8 Technology design constraints | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.1 Doppler frequency shift | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.1.1 Doppler shift due to satellite movement | Considering GEO satellite configuration, a speed of 3m/s for the movement of the satellite (stabilization of the North-South inclination of about 0,07°) and cos(α) = 1, the maximum theorical Doppler frequency shift is calculated at upper limit of MSS core frequency band. The Doppler for average elevations of 15, 30 and... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.1.2 Doppler shift due to UE movement | Depending on the maximum UE speed, the maximum theorical Doppler frequency shift is as follows (at upper limit of MSS core frequency band). The Doppler for average elevations of 15, 30 and 45° is also given for information: ETSI ETSI TR 102 277 V1.2.1 (2007-02) 60 Table 8.2: Maximum Doppler frequency shift due to UE mo... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.2 Interoperability | |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.2.1 Dual mode UEs | To use W-CDMA UTRA FDD with satellite environment means essential parameters are made common between satellite and terrestrial systems. Consequently, most of RF and base-band circuits in the UE can be shared by the two operation modes. The UE antenna is also shared by the two operation modes for the handset configurati... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.2.2 Intermediate Module Repeaters (IMR) | IMR can be built with UTRAN Node B equipment. Co-location with terrestrial Node Bs is possible for system deployment integration. |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.2.3 Inter-system handover | The proposed radio interface eases inter-system handover: • with 2nd generation systems (e.g. GSM or GMR) thanks to compressed mode; • with terrestrial UMTS thanks to the use of the same radio interface (same waveform, same protocol architecture). |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.2.4 Compatibility with existing systems | Since the radio interface is not new but based on terrestrial UMTS, it is highly recommended to reuse terrestrial UMTS components. Furthermore, it presents no problem for connection to terrestrial 3GPP infrastructure thanks to the use of standardized transport interfaces: Iub, Iur and Iu interfaces are kept unchanged f... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.3 Performance enhancement features | For the space segment, communication payload on-board satellite may implement techniques that enhance system performance, e.g.: • transparent analogue connectivity between spots and/or frequency channels: this allows connectivity between coverage areas, thus allowing to easily dispatch S-MBMS services to spots; • regen... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 8.4 System flexibility | The radio interface allows for system flexibility such as: • dynamic spot redirection: a spot coverage may be redirected to a regional area where more capacity is required; • dynamic spot power redistribution: satellite power can be redistributed between spots according to varying capacity requirement; • satellite dive... |
7323b7a140bcb2fd812315fde85112a7 | 102 277 | 9 Conclusion | The present document has presented the feasibility of using W-CDMA as a satellite radio interface. Satellite Multimedia Broadcast/Multicast Service enlarges capacity of terrestrial networks. The main system characteristics can be summarized as: • UMTS terrestrial networks interoperability; • large area coverage, partic... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 1 Scope | The objectives of BSM IP QoS standardization are: • to define what QoS is in the context of the BSM and how to measure it; • to identify what QoS models are applicable to BSMs; • to identify standardized performance metrics that can guarantee the performance of IP over the BSM; and • to provide BSM services at the righ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 2 References | For the purposes of this Technical Report (TR) the following references apply: [1] ETSI TS 101 350: "Digital cellular telecommunications system (Phase 2+); General Packet Radio Service (GPRS); Overall description of the GPRS radio interface; Stage 2 (3GPP 03.64 version 8.9.0 Release 1999)". [2] ETSI TS 123 107: "Univer... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 3 Definitions and abbreviations | |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: availability (measure): percentage of the time the network performs at nominal capacity NOTE: It is also defined as the probability that the network will provide a satisfactory service on demand. availability (performance): ability of ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: 3GPP Third Generation Partnership Project 8-PSK Octagonal Phase Shift Keying ABC Adaptive Bandwidth Control ABR Available Bit Rate AC Admission Control ACK ACKnowledgment ADSL Asymmetrical Digital Subscriber Loop AF Assured Forwarding API Appl... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 4 Overview | QoS and performance aspects cover a wide range of networking topics. In order to focus on BSM specifics the present document addresses only those aspects that impact BSM architectures or are impacted by BSM architectures. In addition, the present document combines the contributions of a number of standardized bodies in... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 5 Introduction | |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 5.1 IP over BSM | The Internet suite of protocols (IP) in BSM networks faces some challenges that may or may not be shared by terrestrial wireline networks. Like the cellular networks, bandwidth is scarce, hence has to be managed carefully. Like some radio networks, availability of network resources can be low due to weather events. Del... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 5.2 Quality of Service | A network with QoS support provides certain priorities and guarantees to specific network traffic. These include but are not limited to: dedicated bandwidth controlled or managed jitter and latency for some real-time and interactive traffic, and predictable end-to-end loss characteristics. These provisions must be made... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 5.3 BSM use cases | As defined in TR 101 984 [11], the BSM offers a general IP service that needs to evolve with the changes in the Internet. In the current context of the present document the use cases include but are not limited to: • point to point connectivity; • Internet access; • content distribution; and • real time multimedia stre... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.1 BSM systems | BSM architectures will have an effect on the behaviour of Internet Protocols (IP). In turn, if IP protocols perform poorly over a certain BSM, overall resource utilization can be low and wasted or the services relying on those protocols will experience outings or degraded quality. BSM QoS involves many layers of the pr... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.1.1 Transparent system | A BSM with a non-regenerative payload (a repeater) is commonly called a "bent-pipe system" or transparent system. This system does not terminate any layers of the BSM protocol stack in the satellite. The satellite simply repeats the signals from the user links to the feeder links transparently. With this system (which ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.1.2 Regenerative satellites (OBP) | A regenerative satellite offers bridging or network functionality in the satellite. Usually, this added functionality is to maximize the efficiency of multi-beam satellites and to improve allocation of spectrum resources on the uplink. In general the OnBoard Processor (OBP) uses an OnBoard Switch (OBS) to send BSM cell... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.1.3 Constellations | While not the focus of this note, constellations of BSMs of different types can also be under consideration. ETSI ETSI TR 102 157 V1.1.1 (2003-07) 21 |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.2 Network architectures | The use cases are provided by BSMs using three main network architectures that support point to point, multicast and broadcast services, namely: • access network; • content distribution to the edge; and • core network. A BSM network can support all three scenarios. However, the present document will give priority to is... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.2.1 BSM protocol stack | The BSM protocol stack [11], following the traditional OSI model, is shown in figure 3. QoS and performance will be defined and measured at the main interface between layers. The SI/SAP interface plays an important role in performance monitoring. It is at that interface that satellite specific performance is translated... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.2.2 BSM topology | A BSM network may support either a mesh or star topology as defined in the Services and Architectures TR 101 984 [11]: • a star network topology is defined by the star arrangement of links between the Hub station (and Gateway) and multiple Remote stations. A Remote station can only establish a direct link with the Hub ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.2.2.1 Access network | The access network as the name indicates allows the users connected to a ST to "access" the Internet (or other network) via a gateway. It uses a star topology and can be realized over both with bent pipe and OBP satellites (figures 4 and 5). Access Terminal Space Segment Gateway Destination Figure 4: Simplified access ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.2.2.2 Meshed network | A meshed network enables peer to peer connectivity (figure 6). While in principle it can be realized over a bent pipe satellite it is more efficient over OBP architectures (figure 7) because of the impact of the double hop on a bent-pipe on low latency services. Terminal Space Segment Terminal Destination Figure 6: Sim... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3 QoS and performance aspects | The BSM architecture defines which system element is involved in QoS and dictates some constraints on the level of performance. The BSM does not specify the QoS requirements: the applications that potentially cross a number of subnetworks define the QoS parameters and the required performance levels. The goal of the BS... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1 Void | |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.1 Network topology | For access networks using a star topology, the QoS management and performance monitoring are located in the gateway and the terminals. The terminal functions will probably be limited to packet level and local functions. The gateway will implement more complex management schemes and centralize the BSM management. As men... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.2 Orbit and delay | Delay over the BSM is due to the time (at the speed of light) needed to reach the orbit of a BSM space segment. Most BSMs are located at the Geostationary Orbit (GSO) with an altitude of approximately 36 000 km. The propagation time for a radio signal to travel twice that distance from a point directly below the satell... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.3 Channel noise | For BSMs most frequency bands under consideration include Ku (12 GHz to 15 GHz) and Ka (20 GHz to 30 GHz) meaning both large bandwidth but also increased transmission disturbances due to weather and atmospheric events: wind that can move ST antennas, rain that induces large fades and scintillation that causes interfere... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.4 Bandwidth | It is well know that spectrum resources (as well as the possible number of satellites in a certain frequency band) are very limited. QoS management requires bandwidth for signalling, maintenance and service differentiation. The BSM cannot allocate bandwidth that does not exist hence tight bandwidth management is centra... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.5 Access schemes | The use of a certain access scheme especially on the uplink also has some impact on the BSM QoS. The focus here is on time division and code division. |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.5.1 TDM(A) and MF-TDMA | Time division access schemes impact overall QoS. There are issues about how time slots (being variable like in DVB-RCS or fixed) can be allocated to requesting session. This is totally under the control of the communication system designers. However, some systems are unable to jump across frequencies in adjacent time s... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.5.2 CDMA | CDMA is not currently deployed in BSM networks but has been envisaged as an access method for ST return channels. However, most CDMA proposals in the 3G/4G mobile communication were developed strictly for voice and do not support broadband multimedia adequately. For example there is no packet scheduling algorithms that... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.6 Onboard processing | Onboard processing's impacts on QoS can be important. They include: - a potential reduced delay for bandwidth allocation if allocation is performed onboard; - the possibility to queue SDUs by traffic class and apply traffic shaping onboard (at the expense of added queuing delay); - the potential of using MPLS-like rout... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.7 Intermittent accessibility | Most broadband systems today (DSL, cable modems, optical interfaces, etc.) are "always on": after an initialization period the system is ready to forward packet without delay. While this is also true for some BSM STs most BSM are based on concepts of bandwidth sharing and bandwidth on demand. This means that if a servi... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 6.3.1.8 Asymmetry | Like ADSL and cable modems, most BSMs are essentially asymmetric. A host connected to a BSM will send all outgoing traffic over a lower rate terrestrial or satellite connection. This asymmetry may have an impact on QoS and overall IP performance. In addition, the DVB-RCS standard was designed for access networks not me... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7 BSM IP QoS management | |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.1 Functional model for BSM QoS | According to the EG 202 009-1 [9] "Quality of Service" (QoS) is defined: "as the collective effect of service performances which determine the degree of satisfaction of a user of a service. It is characterized by the combined aspects of performance factors applicable to all services, such as: - service operability perf... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.2 Traffic and QoS classes | In order to deploy QoS management, traffic classes are defined and their management parameters are negotiated between providers. The use cases and services can help define these classes. This clause presents the traffic classes defined by a number of standardization groups that relate to BSMs. The traffic classes are i... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.2.1 ITU-T | Table 4 presents a set of QoS classes defined in the ITU-T Recommendation Y.1541 [27]. ITU-T Recommendation Y.1541 applies to international end-to-end IP network paths. It defines 6 classes with 4 node mechanisms. The advantage of this classification is the provision of a special signalling class that is needed for tim... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.2.2 TIPHON | ETSI Project TIPHON (Telecommunications and Internet Protocol Harmonization Over Networks) is dedicated to telephony but offers heritage to the BSM QoS. It allows network operators and service providers, to offer those telephony services over multi-protocol packet-and circuit-switched networks, the BSM being one of the... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.2.3 3GPP/UMTS/GPRS | Like for TIPHON the next generation cellular and mobile packet service consider an end-to-end QoS. This results in a number of specific requirements [2]: - QoS attributes (or mapping of them) should not be restricted to one or few external QoS control mechanisms but the QoS concept should be capable of providing differ... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.3 Layer 2 QoS management | This clause introduces how some QoS management can be provided at the layer 2 of the OSI model. While not really network level QoS, this is especially applicable over the BSMs that provide bridging. A number of layer 2 mechanisms for BSM are also introduced. |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.3.1 Ethernet priorities | Ethernet priorities are currently used in virtual LANS (VLANs) and Ethernet over MPLS in Metropolitan Networks. In traditional Ethernet, the Medium Access Control (MAC) protocol is used to provide the data link layer of the Ethernet LAN system. The MAC protocol encapsulates payload data by adding a 14 byte header befor... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.3.2 BSM Layer 2 mechanisms | A Layer 2 (bridge) network is used to interconnect LAN segments. It only forwards valid (i.e. error checked) frames and usually provide filtering of frames based on their source addresses (SA) or other MAC addresses. As was mentioned in the previous clause, the BSM connectivity includes bridging. This clause investigat... |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.3.2.1 MAC Layer mechanisms | These mechanisms are implemented at the frame level and concern mainly the connectivity functions of the BSM. |
ec1da71088ed2b609dd1a945b52a5786 | 102 157 | 7.3.2.1.1 Ethernet priority mapping to BSM priorities | If a BSM is used to interconnect LANs or Virtual LAN (VLAN) using extensions to the Ethernet protocol, then only frame interworking is necessary. The external frames, for example Ethernet are terminated in the ST and either the L2 payload or the IP payload is recovered, segmented and encapsulated into the BSM PDU. The ... |
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