A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with h...A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with high data rates,low latency,and reliability.Therefore,effective handling of INI is crucial to meet the diverse requirements of these applications.To address INI in MN-OFDM systems,this paper proposes a User-Based Numerology and Waveform(UBNW)approach that uses various OFDM-based waveforms and their parameters to mitigate INI.By assigning a specific waveform and numerology to each user,UBNW mitigates INI,optimizes service characteristics,and addresses user demands efficiently.The required Guard Bands(GB),expressed as a ratio of user bandwidth,vary significantly across different waveforms at an SIR of 25 dB.For instance,OFDM-FOFDM needs only 2.5%,while OFDM-UFMC,OFDM-WOLA,and conventional OFDM require 7.5%,24%,and 40%,respectively.The time-frequency efficiency also varies between the waveforms.FOFDM achieves 85.6%,UFMC achieves 81.6%,WOLA achieves 70.7%,and conventional OFDM achieves 66.8%.The simulation results demonstrate that the UBNW approach not only effectively mitigates INI but also enhances system flexibility and time-frequency efficiency while simultaneously reducing the required GB.展开更多
Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept....Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept.While from the user side view,service attractiveness is a dynamic concept related to the variation of different opportunities of users to use the services and capacities.In this paper,a user-based method for measuring service attractiveness is proposed.In this approach,the attractiveness of service for a user is modeled as a function of the user's Travel Times(TT),Free Times(FTs),park size and relative positions of the user,local demanding population,and service.Then,the inequity of attractiveness of services for different users has been examined using three inequity indices including the Duration of Use(DU),Frequency of Visit(FV),and the Chance of Space Choice(CSC).The proposed method is applied to urban regional parks of Tehran municipality.Traffc Analysis Zones(TAZs)and regional parks are respectively regarded as the users and services.In addition to considering inequity of access to the first closest park,the additional cost of accessing to the other two closest parks is also considered.Results show that the proposed method leads to the exploration of the existing inequities of DU,FV,and CSC among residents in local scales,whereas in the service-based method,all users of a service are highlighted with a single value of attractiveness.Comparison of the user-based and service-based attractiveness indices show significant differences.As an example,user-based attractiveness values of about 14%and 20%of TAZs are respectively 5 and 3 square meters more than that of the service-based attractiveness index.However,the service-based method is suitable for regional-scale comparison of the inequities.Therefore,the proposed index can complement the service-based index for inequity mapping and management in varying scales.展开更多
文摘A Mixed Numerology OFDM(MN-OFDM)system is essential in 6G and beyond.However,it encounters challenges due to Inter-Numerology Interference(INI).The upcoming 6G technology aims to support innovative applications with high data rates,low latency,and reliability.Therefore,effective handling of INI is crucial to meet the diverse requirements of these applications.To address INI in MN-OFDM systems,this paper proposes a User-Based Numerology and Waveform(UBNW)approach that uses various OFDM-based waveforms and their parameters to mitigate INI.By assigning a specific waveform and numerology to each user,UBNW mitigates INI,optimizes service characteristics,and addresses user demands efficiently.The required Guard Bands(GB),expressed as a ratio of user bandwidth,vary significantly across different waveforms at an SIR of 25 dB.For instance,OFDM-FOFDM needs only 2.5%,while OFDM-UFMC,OFDM-WOLA,and conventional OFDM require 7.5%,24%,and 40%,respectively.The time-frequency efficiency also varies between the waveforms.FOFDM achieves 85.6%,UFMC achieves 81.6%,WOLA achieves 70.7%,and conventional OFDM achieves 66.8%.The simulation results demonstrate that the UBNW approach not only effectively mitigates INI but also enhances system flexibility and time-frequency efficiency while simultaneously reducing the required GB.
文摘Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept.While from the user side view,service attractiveness is a dynamic concept related to the variation of different opportunities of users to use the services and capacities.In this paper,a user-based method for measuring service attractiveness is proposed.In this approach,the attractiveness of service for a user is modeled as a function of the user's Travel Times(TT),Free Times(FTs),park size and relative positions of the user,local demanding population,and service.Then,the inequity of attractiveness of services for different users has been examined using three inequity indices including the Duration of Use(DU),Frequency of Visit(FV),and the Chance of Space Choice(CSC).The proposed method is applied to urban regional parks of Tehran municipality.Traffc Analysis Zones(TAZs)and regional parks are respectively regarded as the users and services.In addition to considering inequity of access to the first closest park,the additional cost of accessing to the other two closest parks is also considered.Results show that the proposed method leads to the exploration of the existing inequities of DU,FV,and CSC among residents in local scales,whereas in the service-based method,all users of a service are highlighted with a single value of attractiveness.Comparison of the user-based and service-based attractiveness indices show significant differences.As an example,user-based attractiveness values of about 14%and 20%of TAZs are respectively 5 and 3 square meters more than that of the service-based attractiveness index.However,the service-based method is suitable for regional-scale comparison of the inequities.Therefore,the proposed index can complement the service-based index for inequity mapping and management in varying scales.
