基于IEEE802.16的OFDMA系统中的资源分配算法的研究
摘要
随着Internet的发展，数据通信业务增长迅速，而无线的数据通信更给人以全新的感受。目前的无线通信系统如3G、WLAN在数据速率、业务能力及成本、覆盖范围、移动性等方面各有其应用的局限，因此，移动宽带无线接入(MBWA,Mobile Broadband Wireless Access)越来越受到重视。
当前针对3G系统和B3G系统设计的DSSS(直接序列扩频)和Turbo编码已经不能满足未来无线移动通信系统所预计的更高的数据的要求。为了支持50～100Mbit／s，甚至高达1Gbit／s的传输速率，需要采用全新的更加高效的物理层技术。由于实现如此高速的数据传输速率，因此与所占据的信道带宽相比，相干带宽就非常小，从而要求更加复杂的多径处理技术，以解决更多可分解、但又是随机的多径信号。
正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)技术能在频谱效率、频率分集、低速并行数据处理和抗干扰、实现复杂度等方面占有一定优势，使OFDM技术受到广泛关注，并作为新一代移动通信系统的候选方案。基于OFDM技术的发射信号，经过移动通信信道时，将有频率选择性衰落特点，同一用户的不同子载波有不同的衰落；同时，不同用户的衰落又可看成是独立的。为了进一步发挥OFDM技术的特点，利用信息论的注水原理，提出了OFDM的自适应编码调制与子载波功率分配算法。但是，要实现每个子带上精确的功率控制，有较大的实现复杂度与算法的收敛性问题，在具体系统中实现起来较困难。
由于正交频分多址(Orthogonal Frequency Division Multiple Access，OFDMA)系统提供了时间与频率二维资源，可采用OFDM的频分与时分的多址技术即OFDMA来实现系统的多址接入。美国高通公司的HDR(High DataRate，HDR)通信标准采用了在基站按最大功率发射，移动台按接收功率的强弱实现不同的编码调制方案，得到不同速率的数据通信，同时在分配时隙单元上满足一定的公平性原则。这种方法在功率控制上较为简单，但对功率有一定浪费。本文的算法将这种方法与OFDM系统的特点相结合：在比例公平性原则下，按用户数据速率与信道条件进行资源调度，通过对用户子载波组的平均信道参数进行相应的自适应编码调制代替对每个子载波进行功率控制，在降低了实现复杂度的同时，使系统的总的吞吐量为最大。本文通过OPNET仿真工具
As the rapid progress of Internet, data services have grown up fast, and all these have brought new taste of the wireless networks. But nowadays wireless systems, such as 3G, WLAN, have some defects in respect of speed, cost, range and mobility. So the mobile broadband wireless access (MBWA) has got more and more attention.
The mobility provided by the transmission of speech and data without the need of a cable connection has lead to the wide integration of mobile telephones and computers in every day's life. With the increase in transmission speed and quality, provided by these techniques new interesting services, e.g. video telephony or the ubiquitous usage of the Internet can be provided to the mobile user. However, the benefit of mobility adds a certain cost to the system. Unlike cable connections, wireless systems suffer from a high variance of the delay and the attenuation of the transmitted signals. This effect varies over time and frequency and rises with the data-rate. In order to assure the fault-tolerant transmission, while providing high data rates Orthogonal Frequency Division Multiplexing (OFDM) has been developed. With OFDM the spectrum is separated into small sub-bands, the so-called sub-carriers, which are placed in order to assure a high utilization of the given bandwidth.
OFDM technology has gained much attention these years for its excellent behavior in spectrum utilization, parallel data processing, anti-interfere, etc. And OFDM has been listed as one of the candidate technologies of the next generation communication system. When the signal based on OFDM transmits through the wireless channel, it undergoes the frequency selective loss, and different sub-carriers of one
当前针对3G系统和B3G系统设计的DSSS(直接序列扩频)和Turbo编码已经不能满足未来无线移动通信系统所预计的更高的数据的要求。为了支持50～100Mbit／s，甚至高达1Gbit／s的传输速率，需要采用全新的更加高效的物理层技术。由于实现如此高速的数据传输速率，因此与所占据的信道带宽相比，相干带宽就非常小，从而要求更加复杂的多径处理技术，以解决更多可分解、但又是随机的多径信号。
正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)技术能在频谱效率、频率分集、低速并行数据处理和抗干扰、实现复杂度等方面占有一定优势，使OFDM技术受到广泛关注，并作为新一代移动通信系统的候选方案。基于OFDM技术的发射信号，经过移动通信信道时，将有频率选择性衰落特点，同一用户的不同子载波有不同的衰落；同时，不同用户的衰落又可看成是独立的。为了进一步发挥OFDM技术的特点，利用信息论的注水原理，提出了OFDM的自适应编码调制与子载波功率分配算法。但是，要实现每个子带上精确的功率控制，有较大的实现复杂度与算法的收敛性问题，在具体系统中实现起来较困难。
由于正交频分多址(Orthogonal Frequency Division Multiple Access，OFDMA)系统提供了时间与频率二维资源，可采用OFDM的频分与时分的多址技术即OFDMA来实现系统的多址接入。美国高通公司的HDR(High DataRate，HDR)通信标准采用了在基站按最大功率发射，移动台按接收功率的强弱实现不同的编码调制方案，得到不同速率的数据通信，同时在分配时隙单元上满足一定的公平性原则。这种方法在功率控制上较为简单，但对功率有一定浪费。本文的算法将这种方法与OFDM系统的特点相结合：在比例公平性原则下，按用户数据速率与信道条件进行资源调度，通过对用户子载波组的平均信道参数进行相应的自适应编码调制代替对每个子载波进行功率控制，在降低了实现复杂度的同时，使系统的总的吞吐量为最大。本文通过OPNET仿真工具
As the rapid progress of Internet, data services have grown up fast, and all these have brought new taste of the wireless networks. But nowadays wireless systems, such as 3G, WLAN, have some defects in respect of speed, cost, range and mobility. So the mobile broadband wireless access (MBWA) has got more and more attention.
The mobility provided by the transmission of speech and data without the need of a cable connection has lead to the wide integration of mobile telephones and computers in every day's life. With the increase in transmission speed and quality, provided by these techniques new interesting services, e.g. video telephony or the ubiquitous usage of the Internet can be provided to the mobile user. However, the benefit of mobility adds a certain cost to the system. Unlike cable connections, wireless systems suffer from a high variance of the delay and the attenuation of the transmitted signals. This effect varies over time and frequency and rises with the data-rate. In order to assure the fault-tolerant transmission, while providing high data rates Orthogonal Frequency Division Multiplexing (OFDM) has been developed. With OFDM the spectrum is separated into small sub-bands, the so-called sub-carriers, which are placed in order to assure a high utilization of the given bandwidth.
OFDM technology has gained much attention these years for its excellent behavior in spectrum utilization, parallel data processing, anti-interfere, etc. And OFDM has been listed as one of the candidate technologies of the next generation communication system. When the signal based on OFDM transmits through the wireless channel, it undergoes the frequency selective loss, and different sub-carriers of one
引文
[1] Jun Cai, Xuemin Shen, and Jon W. Mark. "Downlink Resource Management for Packet Transmission in OFDM Wireless Communication Systems". Global Telecommunications Conference, 2003. GLOBECOM '03. IEEE Volume 6, 1-5 Dec. 2003 Page(s):2999-3003 vol.6
[2] Liang Xiao, Anchun Wang, Shidong Zhou, Yan Yao. "A Dynamic Resource Scheduling Algorithm For OFDM System". Communications, 2003. APCC 2003. The 9th Asia-Pacific Conference on Volume 2, 21-24 Sept. 2003 Page(s):444-447 Vol.2
[3] Seokjoo Shin and Byung-Han Ryu. "Packet Loss Fair Scheduling Scheme for Real-Time Traffic in OFDMA Systems". ETRI Journal, Volume 26, Number 5, October 2004
[4] E. Lawrey, "Multiuser OFDM", ISSPA 1999, vol 2, pp.761-764, Aug. 1999.
[5] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[6] C. Eklund, R. B. Marks, K.L. Stanwood, S. Wang, "IEEE standard 802.16: a technical overview of the WirelessMAN air interface for broadband wireless access," IEEE Communications Magazine, vol.40, no.6, pp. 98-107, June 2002.
[7] J. Chuang and N. Sollenberger, "Beyond 3G: Wideband wireless data access based on OFDM and dynamic packet assignment," IEEE Communications Magazine, vol.38, no.7, pp. 78-87, July 2000.
[8] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[9] C. Y. Wong, R. S. Cheng, K. B. Letaief, etal, "Multiuser OFDM with adaptive subcarrier, bit, and power allocation," IEEE JSAC, vol.17, no.10, pp.1747-1758, Oct. 1999.
[10] Matthew Andrews, Krishnan Kumaran, Kavita Ramanan, Alexander Stolyar, Rajiv Vijayakumar, Phil Whiting." CDMA Data QoS Scheduling on the Forward Link with Variable Channel Conditions". Bell Laboratories Lucent Technologies April, 2000
[11] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[12] 佟学俭 罗涛 “OFDM移动通信技术原理与应用”人民邮电出版社
[13] C. Eklund, R. B. Marks, K. L. Stanwood, S. Wang, "IEEE standard 802.16: a technical overview of the WirelessMAN air interface for broadband wireless access," IEEE Communications Magazine, vol.40, no.6, pp. 98-107, June 2002
[14] Hyosoon Park, JunSoek Kim, Sunghoon Yoon, Taehyoun Kim, and Jaiyong Lee. "New Sorting-based Resource Management in OFDMA Wireless Communication Systems". CIC 2004
[15] Slawomir Pietrzyk, Gerard J. M. Janssen, "Radio Resource Allocation for Cellular Networks Based on OFDMA with QoS Guarantees". Global Telecommunications Conference,??2004. GEOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s):2694-2699 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378494.
[16] Stefan Valentin, James Gross. "Scheduling of heterogeneous data streams in the downlink of a dynamic OFDM-FDMA wireless cell". TKN Technical Reports Series, Berlin. November 2004
[17] Kanghee Kim, Insoo Koo, Seokjin Sung and Kiseon Kim. "Multiple QoS Support using M-LWDF in OFDMAAdaptive Resource Allocation". Local and Metropolitan Area Networks, 2004. LANMAN 2004. The 13th IEEE Workshop on 25-28 April 2004 Page(s):217-222 Digital Object Identifier 10.1109/LANMAN.2004.1338435
[18] Inamura, H,, Montenegro, G.., Ludwig, R., Gutov, A., Khafizov, F., "TCP over 2.5G and 3G wireless networks", internet draft,http://www.ieff.org/internet-drafts/drafts-ietf-pile-2.5g3g06.txt
[19] Allman, M, Floyd, S., partridge, C., "Increasing TCP's Initial Window", experimental protocol RFC2414, http://www.frags.org/rfcs/rfc2414.html
[20] Harri Holma，Antti Toskala，“WCDMA技术与系统设计——第三代移动通信系统的无线接入”第二版 机械工业出版社 2005
[21] C. Y. Wong, R. S. Cheng, K. B. Letaief, etal, "Multiuser OFDM with adaptive subcarrier, bit, and power allocation," IEEE JSAC, vo1.17, no.10, pp.1747-1758, Oct. 1999.
[22] Hassan Yaghoobi, "Scalable OFDMA Physical Laver in IEEE 802.16 WirelessMAN", Intel Communications Group, Intel Corporation
[23] IEEE Std 802.11a-1999, Part 11, "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications; high-speed physical layer in the 5 GHz band."
[24] IEEE 802.11g-2003, "IEEE Standard for Information technology, telecommunications and information exchange between systems, local and metropolitan area networks, specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, Amendment 4: further higher-speed physical layer extension in the 2.4 GHz band."
[25] IEEE standard for conformance to ieee 802.16 part 1: protocol implementation conformance statement (PICS) proforma for 10-66 GHz wirelessman-SC air interface IEEE Std 802.16/Conformance01-2003 2003 Page(s):0_1-130
[26] IEEE recommended practice for local and metropolitan area networks. Coexistence of fixed broadband wireless access systems IEEE Std 802.16.2-2004 (Revision of IEEE Std 802.16.2-2001) 2004
[27] IEEE P802.16e, "draft amendment to IEEE standard for local and metropolitan area networks, Part 16: air interface for fixed and mobile broadband wireless access systems,??amendment for physical and medium access control layers for combined fixed and mobile operation in licensed bands ."
[28] Theodore S．Rappaport“无线通信原理与应用”电子工业出版社2002
[29] 徐国鑫，纪阳，田辉，张平“用于OFDMA系统的延迟公平资源调度方法”计算机工程与应用 2005．5
[30] 符初生，张忠培“基于OFDM．A资源调度分配算法的研究”电子科技大学学报 2003．10第32卷第5期
[31] 路杨，彭木根，王文博“IEEE802.16标准中OFDM技术研究”中国无线电 2005．2
[32] Qingwen Liu, Shengli Zhou, and Georgios B, Giannakis "Cross-layer Modeling of Adaptive Wireless Links for QoS Support in Multimedia Networks". Proceedings of the First International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE'04) 2004
[33] Farrokh R. Farrokhi, Masoud Olfat, Mehdi Alasti, and K, J. Ray Liu "Scheduling Algorithms for Quality of Service Aware OFDMA Wireless Systems" GlobalTelecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s):2689 - 2693 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378493
[34] Mun Choon Chan and Ramachandran Ramjee "TCP/IP Performance over 3G Wireless Links with Rate and Delay Variation" MOBICOM'02 September 23-28, Atlanta, Georgia, USA 2002
[35] Slawomir Pietrzyk and Gerard J. M. Janssen "Radio Resource Allocation for Cellular Networks Based on OFDMA with QoS Guarantees" Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s): 2694-2699 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378494
[36] 刘培，葛建华，刘刚“多用户自适应调制OFDM系统的高效子载波分配方案”电子与信息学报第26卷第6期2004．6
[37] Hanbyul Seo and Byeong Gi Lee "A Proportional-Fair Power Allocation Scheme for Fair and Efficient Multiuser OFDM Systems" Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 6, 29 Nov.-3 Dec. 2004 Page(s): 3737-3741 Vol.6 Digital Object Identifier 10.1109/GLOCOM.2004.1379067
[38] Cai, J. Shen, X. Mark, J. W "Downlink resource management with adaptive modulation and dynamic scheduling for OFDM wireless communication systems" Wireless Communications and Networking Conference, 2004. WCNC. 2004 IEEE Volume 4, 21-25 March 2004 Page(s):2143-2147 Vol.4
[39] GuoSong Chu, Deng Wang, Shunliang Mei "A QoS architecture for the MAC protocol of IEEE 802.16 BWA system Communications", Circuits and Systems and West Sino??Expositions, IEEE 2002 International Conference on Volume 1, 29 June-1 July 2002 Page(s):435-439 vol.1
[40] Wongthavarawat, K. Ganz, A. "IEEE 802.16 based last mile broadband wireless military networks with quality of service support". Military Communications Conference, 2003. MILCOM 2003. IEEE Volume 2, 13-16 Oct. 2003 Page(s):779-784 Vol.2 Digital Object Identifier 10.1109/MILCOM. 2003.1290211
[41] 侯自强“对发展3G和移动无线宽带接入技术的思考”中兴通讯技术2004年10月10日第5期(总第56期)
[42] "IEEE 802.16 and WiMAX Broadband Wireless Access for Everyone" Intel white paper
[43] 王文博，张金文 “OPNET Modeler与网络仿真” 人民邮电出版社 2003
[44] 陈敏 “OPNET网络防真” 清华大学出版社 2004
[2] Liang Xiao, Anchun Wang, Shidong Zhou, Yan Yao. "A Dynamic Resource Scheduling Algorithm For OFDM System". Communications, 2003. APCC 2003. The 9th Asia-Pacific Conference on Volume 2, 21-24 Sept. 2003 Page(s):444-447 Vol.2
[3] Seokjoo Shin and Byung-Han Ryu. "Packet Loss Fair Scheduling Scheme for Real-Time Traffic in OFDMA Systems". ETRI Journal, Volume 26, Number 5, October 2004
[4] E. Lawrey, "Multiuser OFDM", ISSPA 1999, vol 2, pp.761-764, Aug. 1999.
[5] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[6] C. Eklund, R. B. Marks, K.L. Stanwood, S. Wang, "IEEE standard 802.16: a technical overview of the WirelessMAN air interface for broadband wireless access," IEEE Communications Magazine, vol.40, no.6, pp. 98-107, June 2002.
[7] J. Chuang and N. Sollenberger, "Beyond 3G: Wideband wireless data access based on OFDM and dynamic packet assignment," IEEE Communications Magazine, vol.38, no.7, pp. 78-87, July 2000.
[8] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[9] C. Y. Wong, R. S. Cheng, K. B. Letaief, etal, "Multiuser OFDM with adaptive subcarrier, bit, and power allocation," IEEE JSAC, vol.17, no.10, pp.1747-1758, Oct. 1999.
[10] Matthew Andrews, Krishnan Kumaran, Kavita Ramanan, Alexander Stolyar, Rajiv Vijayakumar, Phil Whiting." CDMA Data QoS Scheduling on the Forward Link with Variable Channel Conditions". Bell Laboratories Lucent Technologies April, 2000
[11] E. Lawrey, "Adaptive Frequency Hopping for Multiuser OFDM", ICICS 1999.
[12] 佟学俭 罗涛 “OFDM移动通信技术原理与应用”人民邮电出版社
[13] C. Eklund, R. B. Marks, K. L. Stanwood, S. Wang, "IEEE standard 802.16: a technical overview of the WirelessMAN air interface for broadband wireless access," IEEE Communications Magazine, vol.40, no.6, pp. 98-107, June 2002
[14] Hyosoon Park, JunSoek Kim, Sunghoon Yoon, Taehyoun Kim, and Jaiyong Lee. "New Sorting-based Resource Management in OFDMA Wireless Communication Systems". CIC 2004
[15] Slawomir Pietrzyk, Gerard J. M. Janssen, "Radio Resource Allocation for Cellular Networks Based on OFDMA with QoS Guarantees". Global Telecommunications Conference,??2004. GEOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s):2694-2699 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378494.
[16] Stefan Valentin, James Gross. "Scheduling of heterogeneous data streams in the downlink of a dynamic OFDM-FDMA wireless cell". TKN Technical Reports Series, Berlin. November 2004
[17] Kanghee Kim, Insoo Koo, Seokjin Sung and Kiseon Kim. "Multiple QoS Support using M-LWDF in OFDMAAdaptive Resource Allocation". Local and Metropolitan Area Networks, 2004. LANMAN 2004. The 13th IEEE Workshop on 25-28 April 2004 Page(s):217-222 Digital Object Identifier 10.1109/LANMAN.2004.1338435
[18] Inamura, H,, Montenegro, G.., Ludwig, R., Gutov, A., Khafizov, F., "TCP over 2.5G and 3G wireless networks", internet draft,http://www.ieff.org/internet-drafts/drafts-ietf-pile-2.5g3g06.txt
[19] Allman, M, Floyd, S., partridge, C., "Increasing TCP's Initial Window", experimental protocol RFC2414, http://www.frags.org/rfcs/rfc2414.html
[20] Harri Holma，Antti Toskala，“WCDMA技术与系统设计——第三代移动通信系统的无线接入”第二版 机械工业出版社 2005
[21] C. Y. Wong, R. S. Cheng, K. B. Letaief, etal, "Multiuser OFDM with adaptive subcarrier, bit, and power allocation," IEEE JSAC, vo1.17, no.10, pp.1747-1758, Oct. 1999.
[22] Hassan Yaghoobi, "Scalable OFDMA Physical Laver in IEEE 802.16 WirelessMAN", Intel Communications Group, Intel Corporation
[23] IEEE Std 802.11a-1999, Part 11, "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications; high-speed physical layer in the 5 GHz band."
[24] IEEE 802.11g-2003, "IEEE Standard for Information technology, telecommunications and information exchange between systems, local and metropolitan area networks, specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, Amendment 4: further higher-speed physical layer extension in the 2.4 GHz band."
[25] IEEE standard for conformance to ieee 802.16 part 1: protocol implementation conformance statement (PICS) proforma for 10-66 GHz wirelessman-SC air interface IEEE Std 802.16/Conformance01-2003 2003 Page(s):0_1-130
[26] IEEE recommended practice for local and metropolitan area networks. Coexistence of fixed broadband wireless access systems IEEE Std 802.16.2-2004 (Revision of IEEE Std 802.16.2-2001) 2004
[27] IEEE P802.16e, "draft amendment to IEEE standard for local and metropolitan area networks, Part 16: air interface for fixed and mobile broadband wireless access systems,??amendment for physical and medium access control layers for combined fixed and mobile operation in licensed bands ."
[28] Theodore S．Rappaport“无线通信原理与应用”电子工业出版社2002
[29] 徐国鑫，纪阳，田辉，张平“用于OFDMA系统的延迟公平资源调度方法”计算机工程与应用 2005．5
[30] 符初生，张忠培“基于OFDM．A资源调度分配算法的研究”电子科技大学学报 2003．10第32卷第5期
[31] 路杨，彭木根，王文博“IEEE802.16标准中OFDM技术研究”中国无线电 2005．2
[32] Qingwen Liu, Shengli Zhou, and Georgios B, Giannakis "Cross-layer Modeling of Adaptive Wireless Links for QoS Support in Multimedia Networks". Proceedings of the First International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE'04) 2004
[33] Farrokh R. Farrokhi, Masoud Olfat, Mehdi Alasti, and K, J. Ray Liu "Scheduling Algorithms for Quality of Service Aware OFDMA Wireless Systems" GlobalTelecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s):2689 - 2693 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378493
[34] Mun Choon Chan and Ramachandran Ramjee "TCP/IP Performance over 3G Wireless Links with Rate and Delay Variation" MOBICOM'02 September 23-28, Atlanta, Georgia, USA 2002
[35] Slawomir Pietrzyk and Gerard J. M. Janssen "Radio Resource Allocation for Cellular Networks Based on OFDMA with QoS Guarantees" Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 4, 29 Nov.-3 Dec. 2004 Page(s): 2694-2699 Vol.4 Digital Object Identifier 10.1109/GLOCOM.2004.1378494
[36] 刘培，葛建华，刘刚“多用户自适应调制OFDM系统的高效子载波分配方案”电子与信息学报第26卷第6期2004．6
[37] Hanbyul Seo and Byeong Gi Lee "A Proportional-Fair Power Allocation Scheme for Fair and Efficient Multiuser OFDM Systems" Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE Volume 6, 29 Nov.-3 Dec. 2004 Page(s): 3737-3741 Vol.6 Digital Object Identifier 10.1109/GLOCOM.2004.1379067
[38] Cai, J. Shen, X. Mark, J. W "Downlink resource management with adaptive modulation and dynamic scheduling for OFDM wireless communication systems" Wireless Communications and Networking Conference, 2004. WCNC. 2004 IEEE Volume 4, 21-25 March 2004 Page(s):2143-2147 Vol.4
[39] GuoSong Chu, Deng Wang, Shunliang Mei "A QoS architecture for the MAC protocol of IEEE 802.16 BWA system Communications", Circuits and Systems and West Sino??Expositions, IEEE 2002 International Conference on Volume 1, 29 June-1 July 2002 Page(s):435-439 vol.1
[40] Wongthavarawat, K. Ganz, A. "IEEE 802.16 based last mile broadband wireless military networks with quality of service support". Military Communications Conference, 2003. MILCOM 2003. IEEE Volume 2, 13-16 Oct. 2003 Page(s):779-784 Vol.2 Digital Object Identifier 10.1109/MILCOM. 2003.1290211
[41] 侯自强“对发展3G和移动无线宽带接入技术的思考”中兴通讯技术2004年10月10日第5期(总第56期)
[42] "IEEE 802.16 and WiMAX Broadband Wireless Access for Everyone" Intel white paper
[43] 王文博，张金文 “OPNET Modeler与网络仿真” 人民邮电出版社 2003
[44] 陈敏 “OPNET网络防真” 清华大学出版社 2004
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