Future Wireless Broadband Networks Challenges and Possibilities IEEE

Future Wireless Broadband Networks: Challenges and Possibilities IEEE 802. 16 Presentation Submission Template (Rev. 9) Document Number: IEEE C 802. 16 -09/0019 r 1 Date Submitted: 2009 -11 -17 Source: Shilpa Talwar, Kerstin Johnsson, Nageen Himayat, E-mail: {shilpa. talwar, kerstin. johnsson , nageen. himayat}@intel. com Jose Puthenkulam, Geng Wu, Caroline Chan, Feng Xue, Minnie Ho, Rath Vannithamby, Ozgur Oyman, Wendy Wong, Qinghua Li, Guangjie Li, Sumeet Sandhu, Sassan Ahmadi, Hujun Yin, Yang-seok Choi , Intel Corporation Venue: Atlanta, GA, USA Base Contribution: None Purpose: For discussion in the Project Planning Adhoc Notice: This document does not represent the agreed views of the IEEE 802. 16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802. 16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: <http: //standards. ieee. org/guides/bylaws/sect 6 -7. html#6> and <http: //standards. ieee. org/guides/opman/sect 6. html#6. 3>. Further information is located at <http: //standards. ieee. org/board/pat-material. html> and <http: //standards. ieee. org/board/pat >.

Future Wireless Broadband Networks Challenges and Possibilities 3/19/2018 2

Agenda • Motivation • Promising Technologies • Recommendations 3/19/2018 3

Motivation 3/19/2018 4

Mobile Performance Today Technology Required Spectrum Standards Completion (Expected) Peak Throughput (Mbps) DL UL Avg. Spectral Efficiency (bits/sec/Hz/Sector) DL Sleep to Active Latency UL 802. 16 e/Mobile Wi. MAX Release 1. 0 2 x 2 MIMO TDD 10 MHz (5: 3) Dec. 2005 40 17 1. 4 0. 7 < 40 ms HSPA (Release 6) FDD 2 x 5 MHz Mar. 2005 14 6 0. 5 0. 3 250 ms HSPA+ (Release 8) 2 x 2 MIMO FDD 2 x 5 MHz Dec. 2008 42 12 0. 8 0. 5 50 ms LTE (Release 8) 2 x 2 MIMO FDD 2 x 10 MHz Mar. 2009 86 38 1. 6 0. 8 10 ms LTE (Release 10) 4 x 4 MIMO FDD 2 x 10 MHz (Q 1 2011) 160 80 2. 4 2. 1 <10 ms 802. 16 m 4 x 4 MIMO TDD 20 MHz (5: 3) (Q 3, 2010) 170 90 2. 9 2. 5 <10 ms All peak throughput numbers (except for Wi. MAX 1. 0) exclude the impact of control & coding overhead 3 GPP data rate numbers are from 3 GPP document TR 25. 912, page 55 and average of NGMN documents for LTE 3 GPP Latency numbers are from 3 GPP 25. 999 & 3 GPP 36. 912 3 GPP LTE Release 10 numbers are from the 3 GPP ITU-R IMT-Advanced submission TR 36. 912 with L=3 for pragmatic overhead calculation Wi. MAX Release 1. 0 uplink assumes virtual MIMO 802. 16 e/Wi. MAX 1. 0 spectral efficiency numbers are based on NGMN evaluation methodology 802. 16 m is based on ITU-R IMT-Advanced submission evaluation and for urban macro –cell 802. 16 m leads in performance. 802. 16 e leads in performance and availability 3/19/2018 5

Commercial Broadband Standards LANs Wireless MANs IEEE 802. 3 Standards* IEEE 802. 11 Standards* IEEE 802. 16 Standards* 802. 11 b (2. 4 GHz) 802. 11 g (2. 4 GHz) 802. 11 a (5 GHz) 802. 11 n (2. 4, 5 GHz) 802. 16 e (Licensed <6 GHz) P 802. 16 m (Licensed <6 GHz) (under development) + + + Current Peak: 10 Gbps Current Peak: 600 Mbps Current Peak: 300 Mbps Target Peak IEEE P 802. 3 ba : 40/100 Gbps Target Peak IEEE P 802. 11 ac (5 GHz): >1 Gbps IEEE P 802. 11 ad (60 GHz): >1 -3 Gbps Target Peak >1 Gbps? Peak Rates of >1 Gbps potential target for Wireless Broadband 3/19/2018 +Logos and trademarks belong to the other entities *Not a complete list of IEEE 802 standards 6

What is happening in the marketplace? • • Broadband traffic is growing exponentially with introduction of new devices: i. Phones and Netbooks Larger screen mobile devices drive up data usage: eg. i. Phone consumes 30 x data Morgan Stanley, Economy + Internet Trends, Oct 2009 i. Phone Netbook Morgan Stanley 3/19/2018 7

Fixed to mobile transition is happening – – – Consumers prefer wireless devices over wired Voice: Users moving from landline to mobile for cost & convenience (ex. Finland has 60% mobile-only households) Internet: “Mobile internet adoption has outpaced desktop” (Morgan Stanley) 3/19/2018 8

Opportunity to connect more devices Boost number of mobile subscribers and devices connected to Internet (e. g. 700 M now in China, 450 M in India) “In the longer term, small wireless sensor devices embedded in objects, equipment and facilities are likely to be integrated with the Internet through wireless networks that will enable interconnectivity anywhere and at anytime” - OECD Policy Brief, June 2008 3/19/2018 9

Challenge – Very High Capacity § Wireless network data usage demand expected to grow by 5 x – 20 x in next 5 -10 years X Increasing device density § Increasing device data rates Spectral Efficiency gains typically limited to 2 -3 x every generation of Air Interface Growth in bandwidth demand is accelerating need for Innovations at all levels 3/19/2018 1

Challenge – Lower Revenue Per Bit • • Service providers are facing challenges at both ends – Invest in network capacity to meet demand – Increase revenue with new applications and services Cost of Network deployments to meet demand is increasing faster than revenue Future networks need to drastically lower Cost per Bit, and enable new Services 3/19/2018 1

Service provider options – the big picture Rationalize Network Usage Invest in Capacity Create New Revenue • Tiered service levels • Buy more spectrum • Exclusive devices • Traffic shaping • Split Cells • Enterprise Services • Deploy new technologies • Applications Store • Deploy multi-tier networks • M 2 M – new business • Exploit multiple protocols Focus of this Presentation is on Technologies with Standards implications 3/19/2018 1

Investing in Capacity Technique Deploy more spectrum Status/Issues Low frequency spectrum is limited & expensive Possibilities Target higher frequencies: 3. 6 -4. 9 GHz (802. 16), 60 GHz (802. 11) Synergistic use with unlicensed bands (802. 11 & 802. 16) Reuse Spectrum Smart Multi-tier Networks reusing same spectrum Limited by infrastructure Cost Link capacity Simple cell splitting, Relays, Pico, Micro, Femto Interference Management Theoretical link capacity nearly achieved (Shannon) Higher order MIMO (4 x 4) capacity in 802. 11 n/16 m Cell capacity Multi-cell/Network Capacity Significant gains harnessed in 802. 16 m: MU-MIMO, MAC enhancements Higher order MU-MIMO Simple techniques included in 16 m: FFR, uplink multi-cell Power Control, Coordinated BF Network MIMO Client co-operation Interference Alignment Expect next set of disruptive gains to come from multi-cell topologies & techniques 3/19/2018 1

Creating New Services M 2 M: automated flow of data from machine to machine M 2 M • Opportunity to boost revenues from $20 billion in 2006 to more than $220 billion by 2010 (Gartner) • M 2 M enables large set of applications Technique Machine-to-Machine Connectivity Status/Issues Networks today can meet needs of high-end applications Low end applications need costeffective solutions Possibilities Optimize air interface for M 2 M • Ultra-Low power • Low cost • Scalability across apps 3/19/2018 1

Promising Technologies 3/19/2018 1

Potential Coverage and Capacity Gains Technique Indoor Coverage Energy Efficiency Carrier Aggregation Spectrum Utilization Cell Capacity Network Capacity 3/19/2018 Avg. Multi-tier Networks Primary Secondary Higher order MIMO Network MIMO Interference Alignment Secondary Primary Secondary Primary Primary Primary Higher order MU-MIMO Client Co-operation Cell-edge Primary Heterogeneous Networks Link Capacity Peak Rate Spectral Efficiency (Macro) Secondary 1

Spectrum Utilization Multi-tier Networks Idea • • • Overlay multiple tiers of cells, macro/pico/femto, potentially sharing common spectrum Client-to-client communication can be viewed as an additional tier (see client co-operation) Tiers can be heterogeneous (802. 16 and 802. 11) Femto/Wi. Fi-AP (Offload Macro-BS) Macro-BS Femto-AP (Indoor coverage & offload macro-BS) Pico-BS (Areal capacity) Client Relay Wireless Access Relay Wireless backhaul Coverage Hole 3/19/2018 1

Spectrum Utilization Advantages of Multi-tier Networks • Significant gains in areal capacity via aggressive spectrum reuse and use of unlicensed bands – E. g. : Co-channel femto-cells provide linear gains in areal capacity with increasing number of femto. AP’s in a multi-tier deployment • Cost structure of smaller cells (pico and femto) is more favorable • Indoor coverage is improved through low cost femto-cells Source: Johansson at al, ‘A Methodology for Estimating Cost and Performance of Heterogeneous Wireless Access Networks’, PIMRC’ 07. Significant potential savings in cost per bit via multi-tier networks 3/19/2018 1

Spectrum Utilization Challenges with Multi-tier Networks • Cross-tier interference • Tiers cause significant interference to each other; problem worse with closed BSs • E. g. Macro/Femto deployment – Closed femto-cell transmissions cause significant interference to macro-users – Interference to data can be addressed with intelligent use of FFR partitions and/or FFZ – Interference to control can not be addressed using FFR or FFZ Max FAP Tx Pwr Outdoor Outage (%) Indoor Outage (%) 50% Outdoor rate (Mbps) 50% Indoor rate (Mbps) 3. 0 17. 0 0. 07 0. 03 No FFZ 40. 2 0. 9 0. 02 16. 3 FFZ 3. 0 0. 5 0. 06 11. 3 No FFZ 76. 2 0. 4 0. 00 21. 4 FFZ Tx Scheme FAP-free zones 3. 0 0. 3 0. 08 7. 95 FFR only 0 d. Bm FFR + Femto-Tx on all FFR partitions • 10 d. Bm Mobility management • At moderate to high speed, handovers across small cells costly • Need intelligent schemes to determine conditions for handover intra- and inter-tiers • SON 3/19/2018 • Need self organization/management across tiers to lower OPEX 1

Spectrum Utilization Heterogeneous Networks Idea • Exploit multiple radio interfaces co-located at the network – Wi. Fi/Wi. MAX interfaces in operator controlled femto-cell networks • Utilize licensed and unlicensed spectrum – Virtual Wi. MAX carrier available through Wi. Fi – Multi-network access possible for single-radio client Integrated Wi. Fi/ Wi. Max Femtocell My. Fi Multi radio device Multi - radio device Wi. MAX WAN Wi. MAX Wi. Fi Wi. MAX/Wi. Fi Mobile Internet Device Wi. Fi Internet Device Simultaneous Virtual Carrier (Wi. Fi) Multi - radio Operation 3/19/2018 Mobile Hotspot 2

Spectrum Utilization Heterogeneous Networks Deployment Scenarios Home Multi-radio Smart-Phone Hotspot Integrated Femto-AP Integrated Pico-cell Enterprise Mobile Hotspot Laptop w/ Wi. Fi & Wi. MAX Multi-radio Device Integrated Femto-AP 3/19/2018 2

Spectrum Utilization Heterogeneous Network Techniques Idea Enhanced Spectrum Description Target Gains Dynamically switch between Increases system Wi. MAX Wi. Fi & Wi. MAX to avoid throughput ~3 x carrier interference Utilization Techniques Virtual Interference Avoidance Diversity/Redundancy Use added spectrum to improve Increases SINR ~3 -5 d. B, Transmission diversity, code rates with decreases cell-edge outage incremental redundancy Carrier Aggregation network Routing/Access ~2 -3 x Qo. S-aware mapping of apps to Improves Qo. S, system different spectrum Multi- Increases peak throughput independent data streams Qo. S/ Load Balancing Use added spectrum to transmit capacity Provide connectivity between Improves connectivity, heterogeneous protocols coverage access 3/19/2018 2

Spectrum Utilization Heterogeneous Network Challenges Network (AP/BS) MRRM Multi-Radio protocols required • Define Generic Link Layer (GLL) * • Manage interworking between heterogeneous links GLL WLAN Wi. MAX OTHER • Define Multi-Radio Resource Management (MRRM) * • Manage radio resources across heterogeneous links Example: Spectrum aggregation WLAN Wi. MAX OTHER GLL • Available in Wi. MAX & Wi. Fi currently • Wi. Fi channel bonding at PHY layer w/ MAC coordination MRRM Multi-Radio Client • Wi. MAX carrier aggregation at MAC layer • Protocols required to combine Wi. Fi & Wi. MAX carriers * WINNER Definition Develop integrated multi-radio protocol design for 802. 16/11 3/19/2018 2

Cell Capacity Client Co-operation Poor WWAN link MID with WWAN & WLAN Good WWAN link Good WLAN link WWAN BS Laptop with WWAN & WLAN Client Cooperation is a technique where clients interact to jointly transmit and/or receive information in wireless environments. Idea: Exploit client clustering and P 2 P communication to transmit/receive information over multiple paths between BS and client. Benefit: Performance improvement in throughput, capacity and reliability without increased infrastructure cost. Usage: Clusters of stationary/nomadic clients with WLAN P 2 P connectivity that share WWAN service provider 3/19/2018 2

Cell Capacity Client Cooperation Gains 3/19/2018 2

Cell Capacity Client Cooperation enabled via 802. 16/11 Wi. MAX frame DL subframe index 0 1 UL subframe index 2 3 4 0 1 2 BS MAP + DL Data Burst (MS & Coop check for allocations given to their Coop STID and listen for bursts) MS Wi. Fi: Coop tx rec’d DL burst to MS. MS tx UL burst to Coop. HARQ + UL Data Burst (MS tx burst) Cooperator UL Data Burst (If Coop successfully rec’d burst from MS, it tx it at same time) 3/19/2018 2

Cell Capacity Client Cooperation Issues • Power – Reduces power consumed by Wi. MAX transmissions • Client Cooperation reduces re-transmissions and boosts MCS per burst – Power consumed by Wi. Fi transmissions is TBD • Power is consumed when MS and cooperator exchange packets; increases with probability of Wi. Fi collisions • Power also consumed by neighbor discovery and cooperator selection protocols • Security – Control and data packets are protected – Sharing MS STID with cooperator may facilitate denial of service attacks • Accounting – Not required, but enabling accounting enlarges market 3/19/2018 2

Cell Capacity Client Cooperation Standards Impacts • 802. 11/Wi. Fi – Peer-to-peer Wi. Fi connectivity required – Neighbor Discovery and Cooperator Selection protocols need to be enabled in P 2 P Wi. Fi mode • 802. 16/Wi. MAX – Enable coordinated Neighbor Discovery opportunities • Speeds up Wi. Fi Neighbor Discovery – saves power • Increases probability of discovery – improves cooperator selection – Provide shared cooperator/MS STID • Establishes cooperative relationship without sharing MS STID • Allows central entity to do accounting 3/19/2018 2

Network Capacity Network MIMO Idea • • Network MIMO algorithms enabled by central cloud processing Cooperative MIMO, Distributed Antennas Converged wireless Cloud Processing server Fiber Distributed Antennas 3/19/2018 DAS with 4 distributed antennas show nearly 300% gain over CAS by utilizing MU MIMO protocol in system evaluation 2

Network Capacity Interference Alignment Idea • Alignment can be across antennas, frequency, time • Benefits: Improves uplink and downlink transmissions of cell-edge users; Rx signal Align transmit directions so that interfering signals all come from the same “direction” (subspace) • Tx signal Low receiver complexity • Sig sub nal spa ce spac sub terf. In Challenge: Practical schemes that can achieve theoretical gain Performance (theory) in high SNR regime: If there are K pairs and each node has M antennas, then KM/2 degrees of freedom are achievable. For comparison, perfect resource sharing achieves 1 degree of freedom. (Cadambe & Jafar 2008) 3/19/2018 3 e

Recommendations • New system/technology needed to drive increased capacity • New radio network topologies needed for lower cost per bit • Plan for next generation 802. 16 standard needed 3/19/2018 3