Литература / UMTS-Report

7.Simulations____________________________________________________________ 374

7.1Simulation cases ___________________________________________________________ 374

7.2Introduction_______________________________________________________________ 374

7.3Validation of simulation chains _______________________________________________ 375

7.4Required Eb/N0’s and C/I’s __________________________________________________ 376

7.4.1Speech _______________________________________________________________________ 376

7.4.2UDD _________________________________________________________________________ 376

7.5Eb/N0 simulation results _____________________________________________________ 378

7.5.1Speech _______________________________________________________________________ 378

7.5.1.1Speech in ITU Indoor_A ______________________________________________________ 378

7.5.1.2Speech in ITU Micro_A ______________________________________________________ 379

7.5.1.3Speech in ITU Vehicular_A ___________________________________________________ 380

7.5.1.4Speech in ITU Vehicular_B____________________________________________________ 381

7.5.2LCD _________________________________________________________________________ 382

7.5.2.1LCD 144 in ITU Micro_A _____________________________________________________ 382

7.5.3UDD _________________________________________________________________________ 383

7.5.3.1UDD in ITU Indoor_A _______________________________________________________ 383

7.5.3.2UDD in ITU Micro_A ________________________________________________________ 385

7.5.3.3UDD in ITU Vehicular_A _____________________________________________________ 387

7.5.3.4UDD in ITU Vehicular_B _____________________________________________________ 389

7.6C/I simulation results _______________________________________________________ 391

7.6.1Speech _______________________________________________________________________ 391

7.6.1.1Speech in ITU Indoor_A ______________________________________________________ 391

7.6.1.2Speech in ITU Micro_A ______________________________________________________ 392

7.6.1.3Speech in ITU Vehicular_A ___________________________________________________ 393

7.6.1.4Speech in ITU Vehicular_B____________________________________________________ 394

7.6.2LCD _________________________________________________________________________ 394

7.6.2.1LCD 384 in ITU Indoor_A ____________________________________________________ 394

7.6.2.2LCD 144 in ITU Micro_A _____________________________________________________ 395

7.6.2.3LCD 384 in ITU Vehicular_A __________________________________________________ 395

7.6.3UDD _________________________________________________________________________ 396

7.6.3.1UDD in ITU Indoor_A _______________________________________________________ 396

7.6.3.2UDD in ITU Micro_A ________________________________________________________ 398

7.6.3.3UDD in ITU Vehicular_A _____________________________________________________ 401

7.6.3.4UDD in ITU Vehicular_B _____________________________________________________ 404

7.6.4Coverage Analysis ______________________________________________________________ 405

7.6.5Discussion_____________________________________________________________________ 406

7.6.6References ____________________________________________________________________ 406

7.7System Level Simulations ___________________________________________________ 407

7.7.1Introduction ___________________________________________________________________ 407

7.7.2Basic assumptions_______________________________________________________________ 407

7.7.2.1General models _____________________________________________________________ 407

7.7.2.2Channel allocation ___________________________________________________________ 407

7.7.2.3Frequency and time hopping ___________________________________________________ 407

7.7.2.4Power control_______________________________________________________________ 407

7.7.2.5Handover __________________________________________________________________ 408

7.7.2.6Link Adaptation _____________________________________________________________ 408

7.7.2.7Type II hybrid ARQ__________________________________________________________ 408

7.7.2.8DTX______________________________________________________________________ 408

7.7.2.9Modulation adaptation ________________________________________________________ 408

7.7.2.10Frequency Planning _________________________________________________________ 408

7.7.2.11Interface between system and link level simulation _________________________________ 408

7.7.3Results _______________________________________________________________________ 409

7.7.3.1Micro cell__________________________________________________________________ 410

7.7.3.2Indoor ____________________________________________________________________ 411

7.7.3.3Macro cell _________________________________________________________________ 414

7.7.4Discussion_____________________________________________________________________ 414

7.8REFERENCES ____________________________________________________________ 415

8.High Level Requirements ________________________________________________ 416

8.1Bearer capabilities _________________________________________________________ 416

8.1.1Maximum user bit rate ___________________________________________________________ 416

8.1.1.1Bearer Service Attributes______________________________________________________ 416

8.1.2Flexibility _____________________________________________________________________ 417

8.1.2.1Minimum bearer capabilities ___________________________________________________ 417

8.1.2.2Service traffic parameters _____________________________________________________ 418

8.1.2.3Performance________________________________________________________________ 418

8.1.3Configuration management________________________________________________________ 419

8.1.4Evolution and modularity _________________________________________________________ 419

8.1.5Handover _____________________________________________________________________ 419

8.1.5.1Overall handover requirements _________________________________________________ 419

8.1.5.2Handover requirements with respect to the radio operating environments ________________ 419

8.2Operational requirements ___________________________________________________ 419

8.2.1Compatibility with services provided by present core networks____________________________ 419

8.2.2Operating environments __________________________________________________________ 420

8.2.2.1Support of multiple radio operating environments __________________________________ 420

8.2.2.2Support of multiple equipment vendors___________________________________________ 420

8.2.3Radio Access network planning ____________________________________________________ 420

8.2.4Public, Private and residential operators______________________________________________ 420

8.2.4.1Public UMTS operators _______________________________________________________ 420

8.2.4.2Private UMTS operators ______________________________________________________ 421

8.2.4.3Residential UMTS operators ___________________________________________________ 421

8.3Efficient spectrum usage ____________________________________________________ 421

8.3.1Spectral Efficiency ______________________________________________________________ 421

8.3.2Variable asymmetry of total band usage ______________________________________________ 421

8.3.3Spectrum utilisation _____________________________________________________________ 421

8.3.4Coverage/capacity_______________________________________________________________ 422

8.3.4.1Development and implementation risk ___________________________________________ 422

8.3.4.2Flexibility of radio network design ______________________________________________ 422

8.3.4.3Synchronisation _____________________________________________________________ 422

8.3.4.4Repeaters and relays _________________________________________________________ 422

8.3.4.5Very large cell sizes__________________________________________________________ 422

8.3.4.6Evolution requirements _______________________________________________________ 422

8.4Complexity / cost___________________________________________________________ 423

8.4.1Mobile Terminal viability_________________________________________________________ 423

8.4.2Network complexity and cost ______________________________________________________ 423

8.4.3Mobile station types _____________________________________________________________ 423

8.5Requirements from bodies outside SMG _______________________________________ 424

8.5.1Alignment with IMT 2000 ________________________________________________________ 424

8.5.2Minimum bandwidth allocation ____________________________________________________ 424

8.5.3Electromagnetic compatibility _____________________________________________________ 424

8.5.4RF Radiation effects _____________________________________________________________ 424

8.5.5Security_______________________________________________________________________ 424

8.5.6Co-existence with other systems ____________________________________________________ 424

8.6Multimode terminal capability _______________________________________________ 425

8.7Services supported by the radio interface ______________________________________ 425

8.7.1Location service ________________________________________________________________ 425

9.Conclusions ___________________________________________________________ 426

10.Annex 1 (ETR04.02) ___________________________________________________ 427

11.Annex 2 : Operators Questions List _______________________________________ 450

11.1Guard band ______________________________________________________________ 450

11.1.1Principle of the analysis _________________________________________________________ 450

11.1.1.1Spurious Emissions of the mobiles _____________________________________________ 451

11.1.1.2BTS receiver characteristics __________________________________________________ 451

11.1.2Considered environments and minimum coupling losses ________________________________ 451

11.1.2.1Indoor Office ______________________________________________________________ 452

11.1.2.2Outdoor to Indoor and Pedestrian ______________________________________________ 452

11.1.2.3Vehicular _________________________________________________________________ 452

11.1.3Synthesis _____________________________________________________________________ 452

11.1.3.1Colocated base stations ______________________________________________________ 452

11.1.3.2Non-colocated base stations___________________________________________________ 453

11.2Spectrum requirements ____________________________________________________ 455

11.3GSM backwards compatibility ______________________________________________ 455

11.4Macro diversity (or soft handover) ___________________________________________ 456

11.5Support of asymmetric traffic _______________________________________________ 457

11.6Operational requirements __________________________________________________ 458

11.7Signalling overhead _______________________________________________________ 459

11.8MAC (Medium Access Control) procedure ____________________________________ 461

11.9System architecture requirements ___________________________________________ 463

11.10Radio network planning___________________________________________________ 463

12.Annex 3 : Spectrum Efficiency Results Using an Analytical Model ______________ 465

12.1Analytical Method ________________________________________________________ 465

12.1.1Analysis Approach _____________________________________________________________ 465

12.1.1.1General Downlink Interference Model __________________________________________ 465

12.1.1.2Handover to adjacent cells____________________________________________________ 469

12.1.2Effect of Link Parameters ________________________________________________________ 470

12.1.2.1Adaptive Modulation ________________________________________________________ 470

12.1.2.2Fractional Loading__________________________________________________________ 471

12.1.2.3Power Control _____________________________________________________________ 471

12.1.3Blocking and Trunking Efficiency _________________________________________________ 471

12.1.4Successful Call Criteria _________________________________________________________ 472

12.1.4.1Voice Calls _______________________________________________________________ 473

12.1.5System Capacity _______________________________________________________________ 474

12.1.5.1Stationary Terminals ________________________________________________________ 474

12.1.5.2Moving terminals___________________________________________________________ 474

12.1.6Procedure for Generation of Results________________________________________________ 474

12.2GSM Spectrum Efficiency __________________________________________________ 476

12.2.1GSM Link Level Performance ____________________________________________________ 476

12.2.2Available GSM channels ________________________________________________________ 476

12.2.3Deployment Results - Indoor Environment __________________________________________ 477

12.2.4Deployment Results - Outdoor environment__________________________________________ 477

12.2.5Conclusions __________________________________________________________________ 478

12.3Spectrum Efficiency of W-TDMA ___________________________________________ 480

12.3.1Deployment Results - Pedestrian Environment________________________________________ 480

12.3.1.1Speech ___________________________________________________________________ 480

12.3.1.2LCD 144 _________________________________________________________________ 480

12.3.2Deployment Results - Vehicular Environment ________________________________________ 481

12.3.2.1Speech ___________________________________________________________________ 481

12.3.2.2LCD384 __________________________________________________________________ 482

12.3.3Deployment Results - Indoor Environment __________________________________________ 483

12.3.3.1Speech ___________________________________________________________________ 483

12.3.3.2LCD384 __________________________________________________________________ 484

12.4Summary of Results _______________________________________________________ 485

Glossary of abbreviations used in:

1. Introduction

Concept group Gamma was set up to define a Wideband TDMA based concept as a proposal for UTRA. The current outcome of the definition and evaluation is presented in this document.

1.1 Contents

In chapters 2 - 5 this document describes the WB-TDMA concept basic building blocks.Chapter 2 introduces the different logical channels and Chapter 3 the physical channels (layer 1). Further, the Logical Link Control (LLC), Radio Link Control (RLC) and Medium Access Control (MAC) are described in Chapter 4. Chapter 5 describes Radio Resource Management (RRM), the radio resource related part of the management plane.

Most of this document describes and evaluates the very basic WB-TDMA. However, there are several attractive and innovative possibilities foreseen to enhance the performance of the scheme. The Chapter 6 will describe some ideas about the possible enhancements.

Evaluation of the concept is based on extensive simulation campaign. Simulations have been completed and the results of these link and system level simulations are reported in chapter 7.

An essential part of any concept is its capability to fulfil the High Level Requirements set by ETSI SMG2. Chapter 8 discusses the presented concept and compares it to the high level requirements. Conclusions are presented in chapter 9.

1.2 Layered structure of the Radio Interface

The WB-TDMA building blocks described in chapter 3 - 5 can be reviewed with the help of the layered structure of the Radio Interface shown in Figure 1-1 below.

Management Plane (ch 5)

RRC/RBC

LLC (ch 4)

RLC/MAC (ch 4)

Layer 1 (ch 3)

Figure 1-1 The Layered Structure of WB-TDMA Radio Interface

The radio interface comprises layered structure with Management, Control and User planes in the GRAN MT and in the GRAN BSS. The management plane extends as a uniform set of functionalities over all the layers and over the control and user planes. The functional entities in the management plane can handle both the inter-layer actions between any of the layers (not only the adjacent layers) and actions targeted to the control and the user planes.

The physical layer (L1) has no division between the control and the user planes.

Table 1-1 Layer 1 of the Evaluated WB-TDMA scheme

The radio link layer (L2) has two sublayers, the LLC sublayer and the RLC/MAC sublayer. The control plane and the user plane are not separated in the LLC sublayer as it offers common Service Access Points (SAP) to access its transport mechanisms. The LLC provides the only service access points of the radio interface for the higher layers. The LLC is intended for both layer 3 signalling and for data transport. The transport mechanisms are provided in either HDLC-mode or minimum mode. The HDLC-mode has error detection, error correction , flow control and segmentation capabilities, whereas minimum mode has only the smallest subset of these.

The RLC/MAC sublayer will offer compact message structures to enable efficient and flexible communication between the peer-to-peer entities over the air interface. The RLC-messages can carry either control or user data messages or both of them in a specified way. The MAC will transport control messages between its peer-to-peer entities. MAC operates in the control plane, as it controls the RLC task to transport Service Data Units (SDU) of the higher layers. State machines for L2 will mostly be the same for the control and the user planes.

The radio network layer (L3) operates in the control plane. It comprises of Radio Bearer Control and Radio Resource Control sublayers. The RNL uses a Service Access Point of the LLC-sublayer to transport its messages between the peer-to-peer entities over the air interface. The RBC protocol has different entities for each radio bearer and it handles procedures for the set-up, negotiation and release of the radio bearers. The RRC protocol handles procedures, which are not directly related to a single bearer, but control the common parameters by e.g. system information, paging, measurement reports, signalling for the algorithms and handover functionality.

User data in this document refers to any data from the user plane of layer 3 or any data from the higher layers. These messages will originate and terminate in the Core Network or in the Mobile Terminal.

2. Logical channels

The purpose of this chapter is to describe the logical channels required for data transfer on UMTS WBTDMA radio interface. All logical channels are unidirectional.

2.1 Control Channels

Control channels are intended to carry L3 and MAC signalling data.

2.1.1 Dedicated Control Channels

Dedicated Control Channels (DCCH) are point-to-point control channels that carry connection oriented messages.

1.Fast Associated Control Channel (FACCH) is a point-to-point channel in the uplink or downlink direction. The allocation of a FACCH is linked to the allocation of a TCH. FACCH is used for the RLC/MAC layer messages, e.g. capacity allocations or link control messages.

2.Stand-alone DCCH (SDCCH) is a point-to-point channel in the uplink or downlink direction. The allocation of a SDCCH is not linked to the allocation of a TCH. SDCCH is used for the RLC/MAC layer messages.

2.1.2 Common Control Channels

Common Control Channels (CCCH) are point-to-multipoint control channels that carry connectionless or connection oriented messages.

1.Broadcast Control Channel (BCCH) is a point-to-multipoint control channel in the downlink direction. A BCCH is intended to broadcast a L3 and MAC signalling data.

2.Paging Channel (PCH) is a point-to-multipoint control channel in the downlink direction. A PCH is intended to broadcast L3 paging messages. The BS-MAC is responsible for ordering transmission on PCH according to L3 paging group information and retransmission requirements.

3.Random Access Channel for short access bursts (S-RACH) is a shared uplink channel and it is used for the messages transmitted in an access burst, e.g. Access Request message.

4.Random Access Channel for normal bursts (N-RACH) is a shared uplink channel and it is used for the messages transmitted in a normal burst, e.g. Capacity Request message and messages related to link adaptation.

5.Forward Access Channel (FACH) is a point-to-multipoint channel in the downlink direction. A FACH is used for transmitting MAC messages to MSs.

6.Uplink Acknowledgement Channel (UACH) is a point-to-point uplink channel which is used by the MSs to acknowledge the reception of message received in the FACH.

7.Forward Order Channel (FOCH) is a point-to-point channel in the uplink direction. A FOCH is used for NRT unit transmission requests for downlink NRT data transfer.

8.NRT Control Channel for downlink traffic (DNCCH) is a point-to-multipoint channel in the downlink direction. A DNCCH is used for broadcasting physical channel allocations and FO scheduling for downlink NRT data transfer. MSs with downlink reservation ID (RID) are expected to listen to DNCCH.

9.NRT Control Channel for uplink traffic (UNCCH) is a point-to-multipoint channel in the downlink direction. A UNCCH is used for broadcasting physical channel allocations and data unit transmission requests for uplink NRT data transfer. MSs with uplink reservation ID (RID) are expected to listen to UNCCH.

10.Public Power Control Channel (PWCCH) is a point-to-multipoint channel in the downlink direction. A PWCCH is used for broadcasting fast power control commands for each allocated timeslot.

11.Frequency Correction Channel (FCCH) is a point-to-multipoint downlink channel that is used by the mobile station to correct its frequency standard to coincide with the frequency standard of the BS.

12.Synchronisation channel (SCH) is a point-to-multipoint downlink channel that is used by the mobile station to synchronise with the TDMA multiframe structure of the BS.

2.2 Traffic Channels

A Traffic Channel (TCH) is used for L3 signalling data and user data transfer.

2.3 Usage of the Dedicated and Common Control Channels

For those messages which can be transmitted on CCCH (N-RACH in uplink, FACH in downlink, UACH always for acknowledging messages transmitted on FACH) or DCCH (SDCCH which allocated capacity or FACCH which uses capacity stolen from TCH) logical channel is selected by MAC. Guidelines for selecting the logical channel are following:

∙If there is one or few MAC messages waiting for transmission, FACCH and CCCH are preferred to SDCCH.

∙If the MS has allocation for a bearer and if the bearer parameters are such that stealing will not cause significant decrease to QoS, transmission on FACCH is preferred to CCCH.

∙SDCCH capacity is allocated when several MAC messages need to be transmitted e.g. during the handover.

2.4 Mapping of Logical Channels to Physical Channels

The purpose of this chapter is to describe the physical resource requirements for the logical channels specified in the previous chapter. Mapping of the control messages onto spread channels is ffs.

2.4.1 Control Channels

2.4.1.1 Dedicated Control Channels

1.Fast Associated Control Channel (FACCH) is mapped to TCH by stealing capacity allocated for a bearer service. FACCH can be mapped on any TCH allocated for the same MAC-identifier to which the MAC message is addressed to.

Multiplexing and demultiplexing of FACCH on/from the traffic channels is done on burst by burst basis by altering between normal and FACCH training sequence. Stolen capacity causes predefined transmission format change to the burst by introducing a puncturing pattern to the transmitted data.

2.Stand-alone Dedicated Control Channel (SDCCH) is mapped to the physical channels according to channel allocation messages.

2.4.1.2 Common Control Channels

1.Broadcast Control Channel (BCCH)

2.Paging Channel (PCH) is interleaved over two to four 1/64 timeslots.

3.Random Access Channel for short access bursts (S-RACH) mapping is derived from cell broadcast. S-RACH is mapped to 1/64 (microcells) or 1/16 (macrocells) timeslots. 1/64 timeslot S-RACH allocation is not mandatory in a cell, in the microcells S-RACH can be mapped to the same physical channel with N-RACH.

4.Random Access Channel for normal bursts (N-RACH) capacity can be dynamically changed and it is derived from cell broadcast. If S-RACH is mapped to the same physical channel with N-RACH, both normal and access bursts are expected. Additional N-RACHs can be dynamically allocated and Control Capacity Allocation can used to indicate selected MSs the new location of N-RACH. N- RACH is mapped to 1/64 timeslots.

5.Forward Access Channel (FACH) capacity can be dynamically changed and it follows a predefined rule derived from cell broadcast. Additional FACHs can be dynamically allocated and Control

Capacity Allocation can used to indicate selected MSs the new location of FACH. FACH is mapped to 1/64 timeslots.

6.Uplink Acknowledgement Channel (UACH) allocation is linked to the allocation of FACH. UACH is also mapped to 1/64 timeslots.

7.Several Forward Order Channels (FOCH) may share the same physical resource. FO is interleaved into two 1/64 timeslots over two subsequent TDMA-frames. The FOCH scheduling is broadcast on the DNCCH.

8.Each NRT Control Channel for downlink traffic (DNCCH) message is mapped over two 1/64 timeslots in subsequent TDMA-frames.

9.Each NRT Control Channel for uplink traffic (UNCCH) message is mapped over two 1/64 timeslots in subsequent TDMA-frames.

10.PWCCH

11.Frequency Correction Channel (FCCH). The frequency correction burst is sent in one 1/64 slot.

12.Synchronisation Channel (SCH). The synchronisation burst can be sent in one 1/64 slot or in one 1/16 slot.

2.4.2 Traffic Channels

A Traffic Channel (TCH) is mapped to the physical channels according to channel allocation messages.

2.4.3 Channel Combinations

At a given moment, a MS accesses only a limited number of the logical channels. One of the following combinations is always accessed:

1.BCCH

2.BCCH + PCH + S-RACH + AGCH

3.BCCH + FACH + UACH + S/N-RACH

4.S/N-RACH + FACH + UACH

Combination 1. is normally used only in the phase when the physical connection is not set.

Combination 2. is used when a MS has no established bearers and is actively listening to the paging messages.

Combination 3. is used after initial access procedure when a MS has established initial bearer.

Combinations 1.- 3. can be accessed on the first RF carrier.

Combination 4. can be used if MS is informed about broadcast information changes via dedicated control channels. If this channel combination should be used, MS is informed about the control channel location which can be on any RF carrier.

In addition to combination 3 and 4 any of the following combinations can be added:

5.SDCCH

6.TCH + FACCH

7.DNCCH + FOCH

8.UNCCH

9.TCH

10.PWCCH

Combinations 5. and 6. are used if a dedicated control channel is needed.

Combination 7. is used by an MS with downlink reservation ID. RF carrier of the DNCCH and downlink transmission is indicated in the NRT-CA message.