The Future of Software Radio: Wireless Network Cloud


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The Future of Software Radio: Wireless Network Cloud

  1. 1. The Future of Software Radio: Wireless Network Cloud Parul Gupta , Smruti Sarangi, Shivkumar Kalyanaraman [IBM Research – India] Zhen Bo Zhu, Lin Chen, Yong Hua Lin, Ling Shao [IBM Research – China]
  2. 2. Outline <ul><li>Cellular wireless systems and convergence trends (esp in emerging markets) </li></ul><ul><li>Today’s 2G/3G architectures and the trend towards 4G (all-IP and OFDMA for PHY/MAC layers) </li></ul><ul><li>Increasing computational costs, low utilization with future generations of technology, upgrade cycles, growing maintenance / OPEX costs. </li></ul><ul><li>SDR evolution: </li></ul><ul><ul><li>Firmware OTA upgrades on vendor platforms, </li></ul></ul><ul><ul><li>From DSP/FPGA platforms to Hybrid IT platforms, </li></ul></ul><ul><ul><li>Multi-technology / multi-operator support </li></ul></ul><ul><ul><li>Virtualization & cloud given fiber-to-tower availability </li></ul></ul>
  3. 3. Wireless: short technical summary Wireless IT convergence Wireless networks are designed to maximize spectral efficiency, support mobility, coverage, and Quality-of-Service under severe spectrum/bandwidth constraints In emerging markets the dependence on wireless is high and growing. ARPU pressures are severe: $2 incremental ARPU today. Operators aggressively outsource their (wireless/wired) networks and IT. <ul><li>Scarce bandwidth </li></ul><ul><li>(10-100 MHz/operator) </li></ul>2. Spectral Efficiency: MHz -> Mbps (signal to noise ratio is key!) Rate Mobility 2G 3G 4G 802.11b WLAN 2G Cellular Other Tradeoffs: Rate vs. Coverage Rate vs. Delay Rate vs. Cost Rate vs. Energy 3. Tradeoffs: Rate vs X (no free lunch!) Today With femto cells & MIMO antennas
  4. 4. Wireless Convergence: Closed Vertically Integrated to Horizontal Open TDMA/CDMA Circuit Voice; Data overlay 2G/3G wireless Integrated MAC, network functions Radio layer: OFDMA/MIMO Network layer: IP Middleware: IMS, SDP Apps: Unified Comms (multimedia), Smarter Planet, mobile VAS, Internet apps, Spoken Web/SMS platforms… 4G wireless <ul><li>System: IT and wireless systems are approaching similar system architectures </li></ul><ul><li>Network Services: Convergence of enterprise wireless and operator wireless services </li></ul><ul><li>Application/Solutions: Seamless integration and interaction of wireless infrastructure and mobile applications </li></ul>Convergence at Systems Level Convergence at Network Services Level Convergence at Application/Solutions Level There is another interesting twist in this wireless / IT convergence at the systems level
  5. 5. Radio network controller Radio network controller Mobile switch center Service support node Gateway PSTN Access Network Core Network 2G-3G wireless network architecture Service Network 4G Wireless Network over Wireless Network Cloud Internet BS cluster BS cluster Cloud of Wireless Access Network + Core Network BS BS BS BS SMS/MMS WAP GW SMS/MMS IMS Content Service Web Service Edge gateway Management Server Billing Edge gateway
  6. 6. Service support node PSTN Service Network 2G/3G/4G Wireless over Wireless Network Cloud Internet BS cluster BS cluster Cloud of Wireless Access Network + Core Network SMS/MMS IMS Content Service Web Service Edge gateway Management Server Billing Edge gateway Service on Edge
  7. 7. Mobile Infrastructure Network Hierarchy Core Network Radio Access Network Challenges : The radio access network is a costly and continuous investment ($100B+). With reducing ARPUs and need for broader nationwide coverage, there are more initiatives for sharing infrastructure
  8. 8. Various Forms of Infrastructure Sharing in Wireless Networks Network Sharing (eg: rural) Base Station Sharing (leads to cloud) Antenna Sharing Tower Sharing (very popular) BSC BTS Owner #1 Retail Owner #2 Retail MSC BSC BTS Owner #1 Network Owner #2 Network BSC BTS BSC BTS Owner #1 Network Owner #2 Network BSC BTS Base Band Unit BSC Owner #1 Network Owner #2 Network BSC SDR BTS RRU O
  9. 9. Towers: Passive vs Active Infrastructure Sharing
  10. 10. Passive Sharing and Tower Companies Eg: Indus Towers (JV controls towers of Bharti, Vodafone, Idea) has 100K towers. Tata Teleservices, Aircel have signed deals with BSNL for sharing 60K+ towers.
  11. 11. Towards Active Sharing: Unbundling Base Stations: RRU + BBU <ul><li>Distributed base station </li></ul><ul><ul><li>RRU (Remote Radio Unit) </li></ul></ul><ul><ul><li>BBU (Base Band Unit) </li></ul></ul><ul><li>Two key standards enable distributed base station development </li></ul><ul><ul><li>CPRI </li></ul></ul><ul><ul><li>OBSAI </li></ul></ul><ul><li>Benefits of distributed base station </li></ul><ul><ul><li>Reduce cost of facilitate infrastructure </li></ul></ul><ul><ul><li>Reduce power consumption </li></ul></ul><ul><ul><li>Easy of installation </li></ul></ul><ul><ul><li>Flexible deployment model </li></ul></ul>Traditional Integrated Macro BS Distributed BS : RRU + BBU RRU BBU
  12. 12. Distributed base station deployment #1: under the tower <ul><li>70% - 80% power consumption is RRUs </li></ul><ul><ul><li>3 RRU: 100 – 150W/RRU </li></ul></ul><ul><ul><li>1 BBU: 100W </li></ul></ul><ul><li>Requirement & Challenges to BBU </li></ul><ul><ul><li>light weight < 10Kg </li></ul></ul><ul><ul><li>small size (1U – 2U) </li></ul></ul><ul><ul><li>low power consumption (< 100W) </li></ul></ul>Scenario #1: Unbundle at the tower BSC BBU MSC BBU RRU RRU <100m RRU-BBU Distance <100m 5-10Km 5-10Km
  13. 13. Software Radio & Software Defined Radio: One way of BBU impln
  14. 14. Multi-Technology Software Radio: 1 BBU Bladecenter vs 5 boxes
  15. 15. Multi- Operator Base Station with Software Radio
  16. 16. Active Infrastructure Sharing: Field Trial in India (IBM/partner)
  17. 17. Unbundled SDR BS w/ Open Wireless Interfaces & IT Platforms
  18. 18. Distributed base station #2: distributed RRU + centralized BBU pool <ul><li>Benefits </li></ul><ul><ul><li>Fit for super urban, urban with high density of traffic </li></ul></ul><ul><ul><li>Highly scalable </li></ul></ul><ul><ul><li>Improve utilization by resource sharing </li></ul></ul><ul><ul><li>Reduce management cost </li></ul></ul><ul><li>Requirements & Challenges to BBU </li></ul><ul><ul><li>High density </li></ul></ul><ul><ul><li>Resource sharing with BBU pool </li></ul></ul><ul><ul><li>Low power consumption </li></ul></ul><ul><li>Key barriers: </li></ul><ul><ul><li>Fiber distance (<10Km) </li></ul></ul><ul><ul><li>Increasing IO data throughput >10Gbs with LTE </li></ul></ul><ul><ul><li>Fiber construction cost </li></ul></ul><ul><ul><li>Synchronization in long distance network </li></ul></ul><ul><li>Case in China: </li></ul><ul><li>World largest TD-SCDMA BBU pool </li></ul><ul><li>Max support 72 RRUs </li></ul><ul><li>Power: 400W </li></ul>A city like Bangalore or Delhi could be served from <10-15 pooled sites. Scenario #2: central deployment BSC BBU Pool RRU BBU BBU BBU BBU MSC 10KM RRU
  19. 19. Wireless Network Cloud: Convergence of IT Platforms, SDR & RRH, Cloud Computing Principles & Fiber-to-the-tower <ul><li>End-to-End IP Infrastructure in 4G </li></ul>IT & Cloud Computing Techniques Software Radio Technology/ Hybrid IT Systems Remote Radio Header Technology Wireless Network Cloud BaseStation Pool Antenna + Remote Radio Header Fiber (> 10Km)
  20. 20. <ul><li>Multiple points collaborate to mitigate ICI </li></ul><ul><li>or align interference for cancellation. </li></ul>Multi-cell environment with frequency reuse factor 1 Optical fiber Optical fiber Optical fiber interference Wireless Network Cloud Potential: Distributed Interference Management. Eg: Collaborative MIMO for Elastic Capacity Allocation
  21. 21. An e2e Demo has been setup in IBM CRL/IRL (WiMAX@2.4GHz) Collaboration of IBM China and India Labs: Multiple base-stations on common IT platform, USRP & e2e flows
  22. 22. BS SDR System Architecture MAC: Software Components MAC and adapter Stacks Control & management Switch of BS system BS edge router MAC instance MAC instance MAC instance Adapter Adapter Adapter Fast path data processing Slow path message processing Scheduling Fragment & packing Packets Encryption Concatenation Packet Extract Defragment & unpacking Packets Decryption MAC Management Downlink Uplink DL Adapter UL Adapter Msg. Msg. Msg. Key technical challenges being addressed (IRL+CRL) <ul><li>How to map the wireless software radio (SWR) stack/workload to massive multicore and hybrid architectures? </li></ul><ul><li>How to meet QoS and real-time requirements for the VoIP application, especially since the wireless software stack (such as PHY and MAC layer) will be implemented in software using a regular OS? </li></ul>
  23. 23. Laundry List of Challenges <ul><li>Difference from regular computational, storage cloud: “ real-time computational cloud ” </li></ul><ul><ul><li>Focus on very high performance, real-time synchronized behavior. </li></ul></ul><ul><ul><li>Cooperative techniques require greater degree of rigor in performance management </li></ul></ul><ul><ul><li>Wireless = Critical infrastructure. Availability / reliability equally important as real-time performance support. </li></ul></ul><ul><li>Choice of underlying platforms : hybrid systems, commodity servers and mapping it to VMs (eg: MAC VM may work well on system A, and PHY VM work well on system B). </li></ul><ul><ul><li>Need real-time virtual switches that can tie together such component VMs into a pipeline (Network -> MAC -> PHY) </li></ul></ul><ul><ul><li>Cooperative techniques require redesign of protocols / implementation </li></ul></ul><ul><li>Multi-tenancy, elastic provisioning of real-time resources, tracking performance / availability risks (eg: 4-5 nines) </li></ul><ul><ul><li>Providing backup for virtual base-stations from multiple data center sites: “cloud” attribute. </li></ul></ul><ul><li>Helping the industry move from an integrated “box” model to a software + outsourced services model. </li></ul><ul><ul><li>Hypothesis: ARPU pressures faced by providers will ultimately drive such a move. Aggressive outsourcing happening in markets like India. </li></ul></ul>
  24. 24. Summary <ul><li>Software radio is an emerging technology. </li></ul><ul><li>The long term potential of software radio involves: </li></ul><ul><ul><li>Unbundling base stations into hardware, software, RF components. </li></ul></ul><ul><ul><li>Application of IT platforms , open wireless interfaces to SDR; opening up a open-source community of developers </li></ul></ul><ul><ul><li>Allowing flexibility for BS software to be virtualized , and consolidated into pools for reduced CAPEX/OPEX, higher utilization and change business models </li></ul></ul><ul><ul><li>Fiber to towers will allow pooling and application of the Cloud model. </li></ul></ul><ul><li>Wireless network cloud can provide new benefits. </li></ul><ul><ul><li>Elastic capacity allocation & higher utilization/lower costs </li></ul></ul><ul><ul><li>Distributed Interference Management: Collaborative MIMO etc (5 th Generation Wireless) </li></ul></ul><ul><ul><li>Integration of edge-based services at the cloud site. Eg: caching, content delivery, unified communications, enterprise app delivery, cloud-based application delivery etc </li></ul></ul><ul><li>Perfect storm of “cloud” challenges: </li></ul><ul><ul><li>Real-time, synchrony/performance-critical, ultra-high reliability requirements. </li></ul></ul>
  25. 25. Terminology <ul><li>RAN – Radio Access Network </li></ul><ul><li>CN – Core Network </li></ul><ul><li>BTS – Base Station = BBU + RRU </li></ul><ul><li>BSC – Base Station Controller </li></ul><ul><li>BBU – Base Band Unit </li></ul><ul><li>RRU – Remote Radio Unit </li></ul><ul><li>RNC – Radio Network Controller, BSC in 3G </li></ul><ul><li>NodeB – BTS in 3G </li></ul><ul><li>eNB – Base Station Node in LTE </li></ul><ul><li>LTE – Long Term Evolution (E-UTRAN) </li></ul><ul><li>AIPN – All IP Network </li></ul><ul><li>NEP – Network Equipment Provider </li></ul>