Wcdma Radio Network Planning And Optimization


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Fundamentals of WCDMA air interface are provided as well as network planning/dimensioning process.

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  • Wcdma Radio Network Planning And Optimization

    1. 1. WCDMA Radio Network Planning and Optimization Song Pengpeng
    2. 2. Contents <ul><li>WCDMA Fundamentals(including link budget fundamentals) </li></ul><ul><li>Radio Resource Utilization </li></ul><ul><li>Coverage and Capacity issues </li></ul><ul><li>Cell deployment </li></ul><ul><li>WCDMA Radio Network Planning(including WCDMA-GSM Co-planning issues ) </li></ul><ul><li>Co-existing TDD & FDD modes </li></ul>
    3. 3. WCDMA Fundamentals <ul><li>WCDMA network infrastructure </li></ul><ul><li>WCDMA radio interface protocol architecture </li></ul><ul><li>WCDMA link level characteristics & indicators </li></ul><ul><li>WCDMA link budget analysis </li></ul>
    4. 4. WCDMA Fundamentals <ul><li>WCDMA Network infrastructure </li></ul>
    5. 5. WCDMA Fundamentals <ul><li>WCDMA Radio Interface protocol architecture </li></ul>
    6. 6. WCDMA Fundamentals <ul><li>Mapping between Trch and PHY channels </li></ul>
    7. 7. WCDMA Fundamentals <ul><li>WCDMA link level indicators </li></ul>WCDMA parameters
    8. 8. WCDMA Radio Network Planning---Example of link budget analysis <ul><li>RF link budget components: </li></ul>
    9. 9. WCDMA Radio Network Planning---Example of link budget analysis Example of RLB for 12.2 kbps voice service(uplink,120km/h,in-car users,VA channel with soft handover) (*) *“modeling the impact of the fast power control on the WCDMA uplink”, sipila,K., Laiho-Steffens,J.,Jasberg,M. and Wacker.A, Proc VTC99’ Spring Huston,Texas,May 1999 pp.1266-1270
    10. 10. RADIO RESOURCE UTILIZATION To adjust the transmit powers in upilnk and downlink to the minimum level required to enshure the demanded QoS Takes care that a connected user is handed over from one cell to another as he moves through the coverage area of a mobile network. Let users set up or reconfigure a radio access bearer(RAB) only if these would not overload the system and if the necessary resources are available. Takes care that a system temporarily going into overload is returned to a non-overloaded situation. To handle all non-realtime traffic,allocate optimum bit rates and schedule transmission of the packet data, keeping the required QoS in terms of throughput and delays. To control the physical and logical radio resources under one RNC;to coordinate the usage of the available hardware resouces and to manage the code tree. <ul><li>Basic RRM functions </li></ul><ul><ul><li>* Power Control </li></ul></ul><ul><ul><li>* Handover Control </li></ul></ul><ul><ul><li>* Congestion Control </li></ul></ul><ul><ul><li>* Resource Management </li></ul></ul>To ensure that the network stays within the planned condition
    11. 11. RADIO RESOURCE UTILIZATION---power control(1) <ul><li>UMTS Power Control(PC) summary </li></ul>
    12. 12. RADIO RESOURCE UTILIZATION---power control(2) <ul><li>Uplink/Downlink inner- and outer- loop power control </li></ul>
    13. 13. RADIO RESOURCE UTILIZATION---handover control <ul><li>Soft-Handover:Example of Soft Handover Algorithm </li></ul>Event 1A: A P-CPICH enters the reporting range Event 1B: A P-CPICH leaves the reporting range Event 1C: A non-active PCPICH becomes better than an active one Event 1D: change of best cell. Reporting event is triggered when any P-CPICH in the reporting range becomes better than the current bet one plus an optional hysteresis value. Event 1E: A P-CPICH becomes better than an absolute threshold plus an optional hysteresis value. Event 1F: A P-CPICH becomes worse than an absolute threshold minus an optional hysteresis value. Addition window drop window
    14. 14. RADIO RESOURCE UTILIZATION---PC and SHO conclusion <ul><li>Bonding of SHO and PC (based on the fact that SHO gain is dependent on the PC efficiency) </li></ul><ul><ul><li>SHO gain depends on the type of channel and the degree of PC imperfection.It is usually higher with imperfect PC. </li></ul></ul><ul><ul><li>SHO diversity can reduce the PC headroom,thus improving the coverage. </li></ul></ul><ul><ul><li>The transmit and receive power differences as a result of SHO measurement errors and SHO windows can affect the PC error rate in uplink,reducing the uplink SHO gains. </li></ul></ul><ul><ul><li>In uplink, SHO gain is translated into a decrease in the outer-loop PC’s Eb/No target. </li></ul></ul>
    15. 15. RADIO RESOURCE UTILIZATION---congestion control <ul><li>Air interface load definition(load control principles) </li></ul><ul><ul><li>Uplink </li></ul></ul><ul><ul><ul><li>Wideband power-based uplink loading </li></ul></ul></ul><ul><ul><ul><li>where </li></ul></ul></ul><ul><ul><ul><li>Throughput-based uplink loading </li></ul></ul></ul><ul><ul><li>Downlink </li></ul></ul><ul><ul><ul><li>Wideband power-based downlink loading </li></ul></ul></ul><ul><ul><ul><li>Throughput-based downlink loading </li></ul></ul></ul><ul><ul><ul><li>or </li></ul></ul></ul>
    16. 16. RADIO RESOURCE UTILIZATION---congestion control (cont’d) <ul><li>Congestion control---keep the air interface load under predefined thresholds </li></ul><ul><ul><li>Admission control---handling all the new traffic </li></ul></ul><ul><ul><li>Load control---managing the situation when system load has exceeded the threshold </li></ul></ul><ul><ul><li>Packet scheduling---handling all the non-real-time traffic </li></ul></ul><ul><li>Admission control </li></ul><ul><ul><li>Wideband power-based admission control </li></ul></ul><ul><ul><ul><li>For uplink, an RT bearer will be admitted if </li></ul></ul></ul><ul><ul><ul><li>where and </li></ul></ul></ul><ul><ul><ul><li>For downlink, an RT bearer will be admitted if </li></ul></ul></ul><ul><ul><li>Throughput-based admission control </li></ul></ul><ul><ul><ul><li>For uplink, it follows </li></ul></ul></ul><ul><ul><ul><li>For downlink, it follows </li></ul></ul></ul>
    17. 17. RADIO RESOURCE UTILIZATION---congestion control (cont’d) <ul><li>Packet scheduling </li></ul><ul><ul><li>Time division scheduling </li></ul></ul><ul><ul><li>Code division scheduling </li></ul></ul>
    18. 18. RADIO RESOURCE UTILIZATION---Code Planning <ul><li>Code planning </li></ul><ul><ul><li>Code allocation is under the control of RNC. </li></ul></ul><ul><ul><li>Code tree may become “fragmented” and code reshuffling is needed(arranged by RNC). </li></ul></ul><ul><li>Code allocation </li></ul><ul><ul><li>Scrambling and spreading code allocation for uplink(by UTRAN) </li></ul></ul><ul><ul><li>Scrambling and spreading code allocation for downlink </li></ul></ul><ul><ul><ul><li>Downlink channelisation code allocation (by UTRAN) </li></ul></ul></ul><ul><ul><ul><li>Downlink scrambling code planning </li></ul></ul></ul><ul><ul><ul><ul><li>512 scrambling codes subdivided into 64 groups each of eight codes </li></ul></ul></ul></ul>
    19. 19. RRM optimization --- SHO optimization(1) <ul><li>Addition window optimization </li></ul><ul><ul><li>Determines the relative difference of the cells at the MS end that are to be included in the active set </li></ul></ul><ul><ul><li>Optimized so that only the relevant cells are in the active set </li></ul></ul>
    20. 20. RRM optimization --- SHO optimization(2) <ul><li>Drop window optimization </li></ul><ul><ul><li>Slightly larger than the addition window </li></ul></ul>Frequent and delayed Hos (cells ping-pong in the active set)
    21. 21. RRM optimization --- SHO optimization(3) <ul><li>Replacement window optimization </li></ul><ul><ul><li>Determines the relative threshold for MS to trigger the reporting Event 1C. </li></ul></ul><ul><ul><ul><li>Too high: slow branch replacement and thus non-optimal active set </li></ul></ul></ul><ul><ul><ul><li>Too low: ping-pong effect with unnecessary SHOs </li></ul></ul></ul>
    22. 22. RRM optimization --- SHO optimization(4) <ul><li>Maximum active set size optimization </li></ul>
    23. 23. RADIO RESOURCE UTILIZATION --- SHO optimization conclusion <ul><li>SHO overhead target level should be 30%~40%. </li></ul><ul><ul><li>Addition window & Drop window optimization should be tuned first </li></ul></ul><ul><ul><li>Change the active set size if needed </li></ul></ul><ul><ul><li>Drop timer value is secondary </li></ul></ul><ul><ul><li>P-CPICH power could be the final parameter for SHO optimization (not recommended!) </li></ul></ul><ul><ul><li>Optimization of active set weighting coefficient to give a stable SHO performance </li></ul></ul>
    24. 24. Coverage and Capacity issues <ul><li>Coverage-limited & Capacity-limited scenarios … </li></ul><ul><li>Coverage & Capacity enhancement methods </li></ul><ul><ul><li>Additional carriers and Scrambling codes </li></ul></ul><ul><ul><li>Mast Head Amplifiers </li></ul></ul><ul><ul><li>Remote RF Head Amplifiers </li></ul></ul><ul><ul><li>Repeaters </li></ul></ul><ul><ul><li>Higher-order Receiver Diversity </li></ul></ul><ul><ul><li>Transmit Diversity </li></ul></ul><ul><ul><li>Beam-forming </li></ul></ul><ul><ul><li>Sectorization </li></ul></ul>
    25. 25. Coverage and Capacity issues---Coverage <ul><li>Different service type(voice@12.2kbps, data@64,144,384kbps)supported with different link budget and thus different coverage range! </li></ul><ul><li>How can coverage be deduced from link budget? link budget  Max Path Loss  cell range  coverage </li></ul><ul><li>Generally, service coverage is uplink limited but system capacity may be limited by either uplink or downlink. </li></ul>Hint: It’s critical to decide whether a specific area should be planned for high data rate service coverage or not
    26. 26. Coverage and Capacity issues---Capacity <ul><li>An uplink-limited scenario --- when the maximum uplink load is reached prior to the base station running out of transmit power. </li></ul><ul><li>An downlink-limited scenario --- when the base station runs out of transmit power and additional users cannot be added without modifying the site configuration. </li></ul><ul><li>Identifying the limited link: </li></ul>
    27. 27. Coverage and Capacity issues---Enhancement methods <ul><li>Coverage & Capacity enhancement methods </li></ul><ul><ul><li>Additional carriers and Scrambling codes </li></ul></ul><ul><ul><ul><li>System capacity is maximized by sharing the power across the available carriers,e.g, two carriers configured with 10W can offer significantly greater capacity than a single carrier configured with 20W does. </li></ul></ul></ul><ul><ul><ul><li>In downlink-limited capacity scenario,the number of supported users depends on the downlink channelisation code orthogonality. It is especially true when higher data rate service is supported in micro-cell. </li></ul></ul></ul><ul><ul><li>Mast Head Amplifiers </li></ul></ul><ul><ul><ul><li>To reduce the composite noise figure of the bse station receiver subsystem. </li></ul></ul></ul><ul><ul><ul><li>But brings bad effects when in downlink-limited scenario. </li></ul></ul></ul><ul><ul><li>Remote RF Head Amplifiers </li></ul></ul><ul><ul><ul><li>To allow the physical separation of base station’s RF and baseband modules. </li></ul></ul></ul><ul><ul><ul><li>Maintaining the same service coverage performance while increasing cell capacity. </li></ul></ul></ul><ul><ul><ul><li>Difference between remote RF head amplifiers and repeaters . </li></ul></ul></ul>
    28. 28. Coverage and Capacity issues---Enhancement methods(cont’d) <ul><li>Coverage & Capacity enhancement methods(cont’d) </li></ul><ul><ul><li>Repeaters </li></ul></ul><ul><ul><ul><li>Used for extending the coverage area of an existing cell, low-cost and ease of installation but introduces delay. </li></ul></ul></ul><ul><ul><ul><li>Slight capacity loss in uplink-limited scenario. </li></ul></ul></ul><ul><ul><ul><li>Applicable in scenarios where clear cell dominance can be achieved such as in rural areas or in tunnels. </li></ul></ul></ul>
    29. 29. Coverage and Capacity issues---Enhancement methods(cont’d) <ul><li>Coverage & Capacity enhancement methods(cont’d) </li></ul><ul><ul><li>Higher-order Receiver Diversity </li></ul></ul><ul><ul><ul><li>To overcome both the impact of fading across radio channel and increase the resulting signal-to-interference ratio. </li></ul></ul></ul><ul><ul><ul><li>Improves uplink performance,especially beneficial for low-speed mobile terminals. </li></ul></ul></ul><ul><ul><li>Transmit Diversity </li></ul></ul><ul><ul><ul><li>Downlink transmit diversity mandatory in 3GPP specifications,e.g. closed-loop mode and open-loop mode. </li></ul></ul></ul><ul><ul><ul><li>Most effective when time- and multipath- diversity is inadequate,e.g. for capacity gain in micro-cell scenario. </li></ul></ul></ul><ul><ul><li>Beam-forming </li></ul></ul><ul><ul><ul><li>An effective technique for improving the downlink performance,especially in environment with a low transmit element. </li></ul></ul></ul><ul><ul><ul><li>High mobile terminal complexity requirement and non-standard functionality configuration. </li></ul></ul></ul>
    30. 30. Coverage and Capacity issues---Enhancement methods(cont’d) <ul><li>Coverage & Capacity enhancement methods(cont’d) </li></ul><ul><ul><li>Sectorization </li></ul></ul><ul><ul><ul><li>A general technique to increase cell capacity where antenna selection is critical. </li></ul></ul></ul><ul><ul><ul><li>May require correspondingly high quantity of hardware with highly sectorisation. </li></ul></ul></ul><ul><ul><ul><li>Usage </li></ul></ul></ul>for typical Micro- cell deployment for typical macro-cell deployment
    31. 31. CELL DEPLOYMENT <ul><li>Hierarchical Cell Structure(HCS) with two or more (FDD) carriers </li></ul><ul><ul><li>Continuous macro-cells to provide full coverage as an “umbrella” layer. </li></ul></ul><ul><ul><li>Micro-cells to accommodate hot-spots with increased capacity and higher bit rates in limited areas. </li></ul></ul><ul><ul><li>Typical air interface capacities are about 1Mbps/carrier/cell for a three-sectored macro BS and 1.5Mbps/carrier/cell for a micro BS. </li></ul></ul><ul><li>Example of WCDMA network evolution </li></ul>An “umbrella” macro cell is best suited for high-mobility users Micro layer provides a very high capacity in a limited area Capacity enhancement
    32. 32. CELL DEPLOYMENT <ul><li>Case study of frequency reuse in micro- and macro- networks </li></ul>Reusing a micro carrier on all macro-cells does not bring any improvements in network performance! Reusing a macro carrier on all micro-cells can support 10% more users than the reference scenario,but extra Power Amplifier needed! Micro-cells do not benefit from the other carrier reused from macro-cells if they still have unused capacity on their own carrier! macro carrier reuse is not worth while when micro-cells locates near macro-cells!
    33. 33. WCDMA Radio Network Planning <ul><li>overview </li></ul><ul><li>Dimensioning </li></ul><ul><li>Detailed planning </li></ul><ul><li>Optimization aspects </li></ul><ul><li>Adjacent carrier interference </li></ul><ul><li>WCDMA & GSM Co-Planning </li></ul>
    34. 34. WCDMA Radio Network Planning---Network planning process overview Definition Planning and Implementation O&M
    35. 35. WCDMA Radio Network Planning ---Dimensioning(1) <ul><li>What is Dimensioning? </li></ul><ul><li>--- to estimate the required site density and site configurations for the area of interest </li></ul><ul><ul><li>Radio Link Budget(RLB) and coverage analysis; </li></ul></ul><ul><ul><li>Capacity estimation </li></ul></ul><ul><ul><li>Estimation of the amount of base station hardware and sites,radio network controllers,equipment at different interfaces and core network elements </li></ul></ul><ul><ul><li>Knowledge of service distribution,traffic density, traffic growth estimates and QoS requirements are essential </li></ul></ul>
    36. 36. WCDMA Radio Network Planning ---Dimensioning(2) <ul><li>Coverage analysis: </li></ul><ul><ul><li>for the single-cell case*: </li></ul></ul><ul><ul><li>where </li></ul></ul><ul><ul><li>where is the received level at the cell edge, is the propagation constant, is the average signal strength threshold and is the standard deviation of the field strength and is the error function. </li></ul></ul><ul><ul><li>for a typical macro-cellular environment </li></ul></ul><ul><ul><ul><li>using Okumura-Hata model, the following formular gives an example for an urban macro-cell with base station antenna height of 25m, mobile station antenna height of 1.5m and carrier frequency of 1950 MHz: </li></ul></ul></ul><ul><ul><ul><li>where is the maximum cell range and is the max path loss. </li></ul></ul></ul>* “Microwave Mobile Communications”, Jakes,W.C, John Wiley& Sons, 1974,126pp
    37. 37. WCDMA Radio Network Planning ---Dimensioning(3) <ul><li>Capacity estimation </li></ul><ul><ul><li>WCDMA capacity and coverage are connected in terms of interference margin. </li></ul></ul><ul><ul><li>Knowledge and vision of subscriber distribution and growth is a must. </li></ul></ul><ul><ul><li>Site configurations such as channel elements,sectors and carriers and site density can be determined. </li></ul></ul><ul><ul><li>Capacity refinement may be obtained in late network optimization. </li></ul></ul><ul><li>RNC dimensioning </li></ul><ul><ul><li>RNC dimensioning limited factors: </li></ul></ul><ul><ul><ul><li>Maximum number of cells(a cell is identified by a frequency and a scrambling code) </li></ul></ul></ul><ul><ul><ul><li>Maximum number of Node B under one RNC </li></ul></ul></ul><ul><ul><ul><li>Maximum Iub throughput </li></ul></ul></ul><ul><ul><ul><li>Amount and type of interfaces(e.g. STM-1,E1) </li></ul></ul></ul>
    38. 38. WCDMA Radio Network Planning ---Dimensioning(4) <ul><li>RNC dimensioning(cont’d) </li></ul><ul><ul><li>The number of RNCs needed to connect a certain number of cells </li></ul></ul><ul><ul><li>The number of RNCs needed according to the number of BTSs to be connected </li></ul></ul><ul><ul><li>the number of RNCs to support the Iub throughput </li></ul></ul><ul><li>Supported traffic (upper limit of RNC processing ability) </li></ul><ul><li>Required traffic(lower limit of RNC processing ability) </li></ul><ul><li>RNC transmission interface to Iub </li></ul>
    39. 39. WCDMA Radio Network Planning ---Detailed Planning(1) <ul><li>Using Radio Network Planning(RNP) tools </li></ul><ul><ul><li>To find an optimum trade-off between quality,capacity and coverage criteria for all the services in an operator’s service portfolio. </li></ul></ul><ul><ul><li>Integrated tools for dimensioning,network planning and optimization. </li></ul></ul><ul><li>Using Static simulator * </li></ul><ul><ul><li>Static simulator flow </li></ul></ul>* “Static simulator for studying WCDMA radio network planning issues”,Wacker.A, Laiho-steffens.J,Sipila.K and Jasberg.M,VTC99’Spring pp2436-2440
    40. 40. WCDMA Radio Network Planning ---Detailed Planning(2) <ul><li>Example of RNP tool workflow </li></ul><ul><li>A plan usually includes parameter settings for the planned network elements such as: </li></ul><ul><li>Digital map& its properties </li></ul><ul><li>Target planning area propagation models </li></ul><ul><li>Antenna models </li></ul><ul><li>Selected radio access technology </li></ul><ul><li>BTS types and site/cell templates </li></ul>Site location,site ground height number of cells and antenna direction <ul><li>Traffic planning: </li></ul><ul><li>Bearer service type and bit rate, </li></ul><ul><li>average packet call size and retransmission rate, </li></ul><ul><li>busy-hour traffic amount and traffic density for </li></ul><ul><li>each service, </li></ul><ul><li>mobile list and WCDMA calculation </li></ul><ul><li>Cite/BTS hardware template may include: </li></ul><ul><li>Maximum number of wideband signal processors </li></ul><ul><li>Maximum number of channel units </li></ul><ul><li>Noise figure </li></ul><ul><li>Available Tx/Rx diversity types </li></ul>A WCDMA cell template may include cell layer type,channel model,Tx/Rx diversity options,power settings, maximum acceptable load, propagation model,antenna infomation and cable losses <ul><li>To verify that the planned coverage, capacity and QoS criteria can be met with te current network deployment and parameter settings: </li></ul><ul><li>Run UL/DL iterations to calculate tx powers for MS and BS </li></ul><ul><li>Snapshot analysis for interference and coverage estimation </li></ul><ul><li>Optimizing dominance </li></ul><ul><li>Propagation models: </li></ul><ul><li>Macro cell---Okumura-Hata model </li></ul><ul><li>Micro cell---Walfisch-Ikegami model </li></ul>
    41. 41. WCDMA Radio Network Planning ---Detailed Planning(3)---UL/DL iteration steps UL iteration steps DL iteration steps
    42. 42. WCDMA Radio Network Planning ---Adjacent Channel Interference <ul><li>Adjacent Channel Interference(ACI) situation </li></ul><ul><ul><li>Adjacent Channel Leakage Power Ratio(ACLR) </li></ul></ul><ul><ul><ul><li>the ratio of the transmitted power to the power measured in an adjacent channel </li></ul></ul></ul><ul><ul><li>Adjacent Channel Selectivity(ACS) </li></ul></ul><ul><ul><ul><li>the ratio of the receive filter attenuation on the assigned channel frequency to the receive filter attenuation on the adjacent channels </li></ul></ul></ul><ul><ul><li>Adjacent Channel Protection(ACP) </li></ul></ul><ul><ul><ul><li>The ratio of adjacent channel power received by the base station as adjacent channel interference power </li></ul></ul></ul>UL adjacent channel interference situation
    43. 43. WCDMA Radio Network Planning ---Adjacent Channel Interference <ul><li>Worst ACI cases---when a macro MS is coming too close to a micro BS </li></ul><ul><ul><li>Minimum Coupling Loss(MCL) </li></ul></ul><ul><ul><ul><li>the smallest path loss between the transmitters and receivers </li></ul></ul></ul><ul><ul><ul><li>For a micro BS and MS, MCL is about 53dB </li></ul></ul></ul><ul><ul><ul><li>For a macro BS and MS, MCL is about 70dB </li></ul></ul></ul>DL adjacent channel interference situation
    44. 44. WCDMA Radio Network Planning ---Example of Worst ACI case <ul><li>Worst ACI case when sites of different operators not co-located </li></ul>Assuming ACS and ACLR of values 33dB and 45dB respectively, the coupling C between the carriers can be calculated as: This simple example shows that clearly in these cases the DL is the weaker link, i.e. before coming too close to a micro BS, the connection of a macro BS will be dropped due to insufficient DL power and it cannot block the micro BS. For uplink scenario, with a maximum MS power of 21dBm, 53dB for MCL to the micro BS and coupoing between the carriers of C=32.7dB,the received level at the micro BS and be estimated as if the background noise level is dBm, the micro BS would suffer a 38.4 dB noise rise form one macro user, which is located in the radio sense at the MCL distance form the micro BS, i.e. such a macro user would completely block the micro BS. For downlink scenario, supposing the micro BS is transmitting with a minimum power of 0.5W(27dBm); then the received interference at the MS in the adjacent channel is Assuming speech service (processing gain of Gp=25dB) with an Eb/No requirement at the Ms of 5dB and an allowed noise rise in the macro cell of 6 dB, the maximum allowed propagation loss Lp to keep the uplink connection working is if we further consider a DL Tx Eb/No requirement of 8dB, the transmit power would need to be
    45. 45. WCDMA Radio Network Planning ---Optimization aspects(1) <ul><li>Guidelines for Radio Network Planning to avoid ACI in multi-operator environment </li></ul><ul><ul><li>Base station and antenna locations </li></ul></ul><ul><ul><ul><li>Co-locate BSs </li></ul></ul></ul><ul><ul><ul><li>Deploy the antennas in a position as high as possible </li></ul></ul></ul><ul><ul><li>Base station configuration </li></ul></ul><ul><ul><ul><li>Optimum antenna beam-width </li></ul></ul></ul><ul><ul><ul><li>“ desensitisation”---increasing the noise figure </li></ul></ul></ul><ul><ul><li>Inter-frequency handovers </li></ul></ul><ul><ul><li>Inter-system handovers </li></ul></ul><ul><ul><li>Guard bands </li></ul></ul>
    46. 46. WCDMA Radio Network Planning ---Optimization aspects(2) <ul><li>Site locations and configurations </li></ul><ul><ul><li>Antenna installations(cable losses) </li></ul></ul><ul><ul><li>Optimum antenna tilting angle and correct antenna selection </li></ul></ul><ul><ul><li>Optimum sectorisation regarding to number of users and SHO overhead.* </li></ul></ul><ul><li>Usage of mast head amplifier(MHA)** </li></ul><ul><ul><li>Used in uplink direction to compensate for the cable losses </li></ul></ul><ul><ul><li>Improved uplink coverage probability </li></ul></ul><ul><ul><li>May have negative effect on downlink performance in case of downlink-limited scenario </li></ul></ul>* “The impact of the base station sectorisation on WCDMA Radio Network Performance”,A.Wacker,J.Laiho-Steffens,K.Sipila,K.Heiska,VTC99’Amsterdam. ** “The impact of the Radio Network Planning and Site Configuration on the WCDMA Network Capacity and Quality of Service”,J.Laiho-Steffens,A.Wacker, P.Aikio,VTC2000
    47. 47. <ul><li>Examples of maximum path losses with existing GSM and WCDMA system </li></ul>WCDMA-GSM Co-Planning Issues
    48. 48. WCDMA-GSM Co-Planning Issues---interference issues <ul><li>Interference between the two system is the main issue </li></ul><ul><ul><li>Radio frequency issue </li></ul></ul><ul><ul><ul><li>Second harmonics of GSM900 could probably fall into WCDMA uplink band </li></ul></ul></ul><ul><ul><ul><li>Third-order inter-modulation products of PCS 1800 could be problematic </li></ul></ul></ul>Second-order harmonic distortion from GSM900 falling into WCDMA band
    49. 49. WCDMA-GSM Co-Planning Issues ---interference issues <ul><ul><li>Interference mechanisms from GSM system to WCDMA system </li></ul></ul><ul><ul><ul><li>Adjacent Channel Interference(ACI) :depends on Tx/Rx filter and spatial and spectral distance between the own and adjacent carrier,the cell type and the power levels used. </li></ul></ul></ul><ul><ul><ul><li>Wideband Noise(WB) :from all out-of-band emission components. </li></ul></ul></ul><ul><ul><ul><li>Cross-modulation(XMD) : depends on non-linearity of the MS receiver,the duplex isolation and the transmitting mobile power. </li></ul></ul></ul><ul><ul><ul><li>Inter-Modulation Distortion(IMD) :caused by non-linearities of RF components of transmitter or receiver. </li></ul></ul></ul>XMD is proportional to the square of transmitting power and very sensitive to the Tx power of the MS! Typically in micro-cells and could be reduced by guard band. Third-order IMD with mixture of products of the GSM carrier frequencies f1 and f2: 2f1-f2 or 2f2-f1
    50. 50. WCDMA-GSM Co-Planning Issues Handover GSM  WCDMA for capacity extension or service optimization Handover WCDMA-GSM for coverage extension Antenna sharing and co-located sites could be preferable.
    51. 51. Co-existing TDD & FDD modes ---UTRA TDD mode <ul><li>Some key parameters for the UTRA FDD and TDD modes </li></ul>Rather low spreading factors makes it inadequate to reuse all the timeslots in all the cells.That is,network must control which slots and directions are used in which cells. Not as fast as to follow fast fading pattern!
    52. 52. Co-existing TDD & FDD modes---Example of TDD RLB uplink/downlink Greater Eb/No difference between with or without RxD! Smaller Max path loss than that of FDD scenario  TDD cells have smaller radius!
    53. 53. Co-existing TDD & FDD modes--- TDD/TDD interference <ul><li>Interference scenarios </li></ul><ul><li>TDD-TDD Interference scenarios /solutions </li></ul><ul><ul><li>MS to MS interference --- when MS1 is transmitting while MS2 is receiving, especially at cell borders. </li></ul></ul><ul><ul><ul><li>Cannot be avoided by network planning,but may benefit from </li></ul></ul></ul><ul><ul><ul><ul><li>DCA and radio resource management </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Power control </li></ul></ul></ul></ul><ul><ul><li>BS to BS interference --- when BS1 is transmitting while BS2 is receiving </li></ul></ul><ul><ul><ul><li>depends heavily on BS locations. </li></ul></ul></ul><ul><ul><ul><li>Could be avoided by providing sufficient coupling loss between base stations </li></ul></ul></ul><ul><ul><ul><li>BSs better be synchronized and of same asymmetry. </li></ul></ul></ul>
    54. 54. Co-existing TDD & FDD modes --- TDD/FDD interference <ul><li>TDD-FDD Interference scenarios /solutions </li></ul><ul><ul><li>TDD MS to FDD BS </li></ul></ul><ul><ul><ul><li>To make FDD/BS less sensitive,especially for small pico cells </li></ul></ul></ul><ul><ul><ul><li>To place BS antenna as high as possible from TDD MSs </li></ul></ul></ul><ul><ul><li>FDD MS to TDD BS </li></ul></ul><ul><ul><ul><li>Inter-frequency or inter-system may be helpful </li></ul></ul></ul><ul><ul><li>FDD MS to TDD MS </li></ul></ul><ul><ul><ul><li>Use downlink power control of TDD BS to compensate for the interference from FDD MS </li></ul></ul></ul><ul><ul><ul><li>Inter-system/inter-frequency handover </li></ul></ul></ul>Interference mainly between TDD and FDD/UL frequency bands!
    55. 55. Co-existing TDD & FDD modes <ul><li>UTRA TDD </li></ul><ul><ul><li>Advantage in the unpaired spectrum operation </li></ul></ul><ul><ul><li>Better utilized for asymmetric service at high data rate </li></ul></ul><ul><ul><li>Can build stand-alone wide-area TDD network(?) or serve as a separate capacity-enhancing layer in the network </li></ul></ul><ul><ul><li>Lower Max. Path loss compared with FDD scenario </li></ul></ul><ul><ul><li>Lower “cell breathing” and thus more stable service coverage </li></ul></ul><ul><ul><li>Requires strict synchronization especially in uplink </li></ul></ul><ul><ul><li>Low-rate services often goes to code-limited cases while high-rate services goes to interference-limited cases </li></ul></ul>From the service point of view, UTRA TDD is most suited for small cells and high data rate services!
    56. 56. Thanks!