Magic Radio: The Killer Solution to Spectrum Efficiency
Release Date：2016-03-16
By Zheng Lingxia
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Challenges
Because mobile broadband develops, LTE networks are being widely deployed at 900 MHz and 1800 MHz. This means that more GSM spectrums are being refarmed for LTE.
Traditionally, GSM spectrums are statically re-allocated to LTE. However, as traffic load changes dynamically, and busy hours for voice and data traffic do not overlap completely, the conventional static spectrum allocation fails to meet LTE needs for on-demand and dynamic bandwidth allocation. 1800 MHz band has become the core band for LTE and also the bearer frequency for GSM; so many operators need to refarm their GSM spectrums when deploying LTE networks. Because LTE voice is not yet mature, GSM at 1800 MHz is still being used to bear voice service in a short term. Therefore, a major challenge for multi-network operators is to implement GSM/LTE collaborative spectrum scheduling to offer both voice and data services to users.
Traditionally, GSM spectrums are statically re-allocated to LTE. However, as traffic load changes dynamically, and busy hours for voice and data traffic do not overlap completely, the conventional static spectrum allocation fails to meet LTE needs for on-demand and dynamic bandwidth allocation. 1800 MHz band has become the core band for LTE and also the bearer frequency for GSM; so many operators need to refarm their GSM spectrums when deploying LTE networks. Because LTE voice is not yet mature, GSM at 1800 MHz is still being used to bear voice service in a short term. Therefore, a major challenge for multi-network operators is to implement GSM/LTE collaborative spectrum scheduling to offer both voice and data services to users.
Introduction of Magic Radio
ZTE has rolled out its innovative Magic Radio, which can refarm spectrum, adapt to traffic changes, and flexibly schedule GSM/LTE and UMTS/LTE spectrum. Magic Radio helps multi-network operators enhance spectrum efficiency and improve user experience as well.
Magic Radio is designed for flexible spectrum sharing and scheduling between GSM and LTE. It features GSM dynamic frequency allocation, GSM/LTE band-in spectrum overlay, GSM/LTE dynamic bandwidth extension, and GSM/LTE collaborative spectrum scheduling.
GSM dynamic frequency allocation is a unique feature that has been commercially deployed. It brings GSM spectrum gain by allocating and releasing frequency resources according to traffic tide (except some higher-priority TRX, such as BCCH TRX). The same network capacity can be achieved with less bandwidth and no performance loss. Normally, a 200 KHz guard band is required to mitigate inter-system interference. GSM/LTE band-in spectrum overlay has an innovative filter algorithm and unique bandwidth compression technique that maintains zero or even negative GSM/LTE guard bandwidth and improves spectrum efficiency. For the configuration of 20M LTE bandwidth, GSM can use 1.4 MHz of the 2 MHz reserved bandwidth. GSM/LTE dynamic bandwidth extension supports dynamic spectrum re-farming at LTE narrow bands. It dynamically extends LTE bandwidth when there is low GSM traffic load and can balance GSM and LTE spectrum utilization based on regional GSM traffic statistics. When the GSM traffic load falls below a given threshold, certain GSM spectrum resources are released for LTE. With GSM/LTE collaborative spectrum scheduling, GSM and LTE spectrums are dynamically scheduled in a granularity of 200 KHz according to the traffic load. This improves LTE throughput and user experience.
Magic Radio is designed for flexible spectrum sharing and scheduling between GSM and LTE. It features GSM dynamic frequency allocation, GSM/LTE band-in spectrum overlay, GSM/LTE dynamic bandwidth extension, and GSM/LTE collaborative spectrum scheduling.
GSM dynamic frequency allocation is a unique feature that has been commercially deployed. It brings GSM spectrum gain by allocating and releasing frequency resources according to traffic tide (except some higher-priority TRX, such as BCCH TRX). The same network capacity can be achieved with less bandwidth and no performance loss. Normally, a 200 KHz guard band is required to mitigate inter-system interference. GSM/LTE band-in spectrum overlay has an innovative filter algorithm and unique bandwidth compression technique that maintains zero or even negative GSM/LTE guard bandwidth and improves spectrum efficiency. For the configuration of 20M LTE bandwidth, GSM can use 1.4 MHz of the 2 MHz reserved bandwidth. GSM/LTE dynamic bandwidth extension supports dynamic spectrum re-farming at LTE narrow bands. It dynamically extends LTE bandwidth when there is low GSM traffic load and can balance GSM and LTE spectrum utilization based on regional GSM traffic statistics. When the GSM traffic load falls below a given threshold, certain GSM spectrum resources are released for LTE. With GSM/LTE collaborative spectrum scheduling, GSM and LTE spectrums are dynamically scheduled in a granularity of 200 KHz according to the traffic load. This improves LTE throughput and user experience.
Application and Benefits
All features of Magic Radio have been field proven and result in good network performance and enhanced user experience. Dynamic frequency allocation has been implemented by China Mobile in traffic-tide areas, and spectrum gain has reached as high as 35%. In other words, only 65% of spectrum resources are used, and the remaining spectrum is saved for LTE network. ZTE helps China Mobile achieve the same network capacity without performance degradation.
GSM/LTE band-in spectrum overlay, GSM/LTE dynamic bandwidth extension, and GSM/LTE collaborative spectrum scheduling have also been verified by China Unicom. In the GSM/LTE co-sited scenario, GSM/LTE band-in spectrum overlay enables GSM to obtain more available spectrum from the LTE reserved bandwidth while keeping LTE download rates stable. Moreover, KPIs of the GSM network fluctuate within a normal range, and carriers between 10 MHz and 20 MHz can be aggregated. With GSM/LTE dynamic bandwidth extension, ZTE’s Magic Radio also supports dynamic spectrum re-farming at LTE narrow bands. This helps China Unicom improve spectrum efficiency by more than 50% and double LTE download rates regardless of user location. As a result, both GSM CS and PS services run normally, and user satisfaction is significantly enhanced. The GSM/LTE coordinated spectrum scheduling feature has also been applied in China Unicom’s GSM/LTE network based on user behavior and traffic distribution. When GSM traffic load is above a given threshold, GSM can use free LTE radio bearer for its services. When LTE traffic load is above a given threshold, LTE can use free GSM time slots for its services. This enables real-time GSM and LTE spectrum sharing with a granularity of 200 KHz. Both GSM and LTE networks operate well and their performance KPIs are kept stable. Magic Radio helps China Unicom improve its network bandwidth and throughput and increases spectrum efficiency by more than 40%.
GSM/LTE band-in spectrum overlay, GSM/LTE dynamic bandwidth extension, and GSM/LTE collaborative spectrum scheduling have also been verified by China Unicom. In the GSM/LTE co-sited scenario, GSM/LTE band-in spectrum overlay enables GSM to obtain more available spectrum from the LTE reserved bandwidth while keeping LTE download rates stable. Moreover, KPIs of the GSM network fluctuate within a normal range, and carriers between 10 MHz and 20 MHz can be aggregated. With GSM/LTE dynamic bandwidth extension, ZTE’s Magic Radio also supports dynamic spectrum re-farming at LTE narrow bands. This helps China Unicom improve spectrum efficiency by more than 50% and double LTE download rates regardless of user location. As a result, both GSM CS and PS services run normally, and user satisfaction is significantly enhanced. The GSM/LTE coordinated spectrum scheduling feature has also been applied in China Unicom’s GSM/LTE network based on user behavior and traffic distribution. When GSM traffic load is above a given threshold, GSM can use free LTE radio bearer for its services. When LTE traffic load is above a given threshold, LTE can use free GSM time slots for its services. This enables real-time GSM and LTE spectrum sharing with a granularity of 200 KHz. Both GSM and LTE networks operate well and their performance KPIs are kept stable. Magic Radio helps China Unicom improve its network bandwidth and throughput and increases spectrum efficiency by more than 40%.
Future-Proof
The innovative Magic Radio has been a great success for operators around the world. ZTE has evolved the Magic Radio to accommodate LTE flexible bandwidth configuration and UMTS/LTE dynamic carrier extension. Spectrum efficiency can be further enhanced when Magic Radio is combined with other technologies such as CA.
LTE flexible bandwidth configuration makes possible non-standard bandwidth configuration for both single and multiple carriers. For example, a 4.8 MHz bandwidth can be used as a 5 MHz LTE single carrier without performance loss and a 12.5 MHz bandwidth can be configured as a 10 MHz LTE carrier and a 3 MHz LTE carrier without performance loss. UMTS/LTE dynamic carrier extension enables dynamic UMTS/LTE spectrum sharing based on UMTS traffic load. When UMTS traffic load is lower than a given threshold, UMTS will release some spectrum resources for LTE, and vice versa. In this way, spectrum efficiency can be significantly improved.
LTE flexible bandwidth configuration makes possible non-standard bandwidth configuration for both single and multiple carriers. For example, a 4.8 MHz bandwidth can be used as a 5 MHz LTE single carrier without performance loss and a 12.5 MHz bandwidth can be configured as a 10 MHz LTE carrier and a 3 MHz LTE carrier without performance loss. UMTS/LTE dynamic carrier extension enables dynamic UMTS/LTE spectrum sharing based on UMTS traffic load. When UMTS traffic load is lower than a given threshold, UMTS will release some spectrum resources for LTE, and vice versa. In this way, spectrum efficiency can be significantly improved.
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