EP1303997A4 - Procede pour l'interface aerienne de fa on a supporter un debit de donnees variable - Google Patents

Procede pour l'interface aerienne de fa on a supporter un debit de donnees variable

Info

Publication number
EP1303997A4
EP1303997A4 EP00934846A EP00934846A EP1303997A4 EP 1303997 A4 EP1303997 A4 EP 1303997A4 EP 00934846 A EP00934846 A EP 00934846A EP 00934846 A EP00934846 A EP 00934846A EP 1303997 A4 EP1303997 A4 EP 1303997A4
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EP
European Patent Office
Prior art keywords
codes
code
length
partitions
different
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00934846A
Other languages
German (de)
English (en)
Other versions
EP1303997A1 (fr
Inventor
Daoben Li
Shiu Ming Joseph Ho
Haiyang Gao
Yongsheng Zhang
Weidong Chen
Yuanhua Deng
Frederic Leroudier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linkair Communications Inc
Original Assignee
Linkair Communications Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linkair Communications Inc filed Critical Linkair Communications Inc
Publication of EP1303997A1 publication Critical patent/EP1303997A1/fr
Publication of EP1303997A4 publication Critical patent/EP1303997A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H04W28/18—Negotiating wireless communication parameters

Definitions

  • the present invention relates to a method for the air interface to support variable data rate in a wireless communications system. More particularly, to a method and means for configuring and allocating physical channel resources of the LS coded wireless system to different mobile terminals with data rate requirements.
  • IP Internet Protocol
  • This invention concerns the support of multiple mobile terminals with different data rate requirements.
  • CDMA network multiple access is achieved by the allocation of different multiple access codes to different mobile terminal.
  • classic CDMA systems the support of both best effort packet data services (e.g. Internet browsing, file transfer) on the same radio resource as real-time circuit-like applications such as voice poses the problem of system-wide power and interference management. Preventing a high speed data burst from consuming resource reserved for real-time users is an extremely difficult problem to manage. This is mainly due to the impact of interference on classic CDMA systems. This problem is even more arduous when considering a network where multiple cells can interfere with each others (typical of a high density cellular network).
  • LS code has the special property that the auto correlation of an LS code is zero, except at the origin, when the two copies of the LS codes are synchronized to with a window of n chips.
  • LS code has another special property that the cross correlation between two different LS codes are zero when the two codes are synchronized to with a window of n chips.
  • there is a Zero Correlation Window of size n chips which is also referred to as Interference Free Window.
  • ISI Inter- Symbol-Interference
  • MAI Multiple Access Interference
  • the wireless systems, the signals, the air interface which utilize LS codes as the orthogonal spread codes will be respectively referred to as LS coded wireless systems, LS coded signals, and LS coded air interface.
  • IFW wireless systems the signals, the air interface which utilize orthogonal spread codes with an IFW property
  • IFW wireless systems IFW signals
  • IFW air interface IFW air interface
  • a method is needed that allows the allocation of radio interface resources to different mobile terminals such that the data rate requirements of different mobile terminals can be satisfied.
  • the radio interface resource of an LS coded wireless system can be allocated in multiples of sub frames.
  • the problem of resource allocation is thus a problem of how to configure these sub frames and how to allocate the sub frames to the mobile terminals in an LS coded wireless system, such that the data rate requirement of the mobile terminals can be satisfied.
  • this method should make use of the special intermittent transmission characteristic of packet data traffic such that multiplexing gain can be realized and thus increase radio channel utilization and capacity.
  • the present invention provides a channel resource configuration and allocation method that allows:
  • the air interface is divided into a plurality of partitions in either the time domain, the space domain, the frequency domain, or any combination of them, each partition is allocated a set of LS codes as the orthogonal spread code, and at least two partitions are allocated different sets of LS codes with different code lengths.
  • the method is achieved by utilizing different LS code lengths, within different sub frames and by the flexible allocation of sub frames to each mobile terminal.
  • Figure 1 shows the LAS-2000 frame structure as a preferred embodiment of the present invention, and demonstrates how the frame is further divided into sub frames and time slots.
  • LAS-2000 is an operation mode of the LS coded wireless systems, that is compatible with the IS-2000 standard.
  • FIG. 2 shows a (17, 136, 2559) LA code, which contains LA 17 pulses, and 2559 chips in length. This is intended as an illustrative example only since many other codes of the same family (LA codes) can be used.
  • Figure 3 shows a time-slot within the LS-2000 frame structure. It demonstrates the position of the LS code in relation to the LA pulse.
  • Figure 4 shows the LS code generation tree and demonstrates the relationship between LS code length and the number of available LS codes at each level of the
  • Figure 5 shows the time offset overlap LA code and demonstrates how it is generated from an original LA code.
  • Figure 6 shows the time slots and how multiple LS-codes are arranged within the time slot.
  • Figure 7 shows an example of a time-slot, which carries eight 16 chips (8 chips C code and 8 chips S code) long LS codes.
  • Figure 8 shows the LS code generation tree and explain the concept of sub tree and least common ancestor.
  • Figure 9 demonstrates an example of supporting variable data rate within the LAS-2000 frame structure using LS codes of different length.
  • Figure 10 shows a preferred embodiment of the LAS-2000 data frame structure.
  • LAS-2000 is one example of how this invention can be used.
  • Other examples exist based on the use of other wireless standards such as W-CDMA and TD-SCDMA.
  • Figure 11 demonstrates an example of supporting different data rates in different sub frames of the LAS-2000 frame structure.
  • Figure 12 shows an example of supporting both circuit-based traffic and packet- based traffic within the same LAS-2000 carrier.
  • Figure 13 shows the state diagram of an enhanced 16QAM modulation.
  • the invention relies on the notion that the transmission from a fixed or mobile transmitter of an LS coded wireless system can be separated by the receiver from the transmission from other transmitters by a number of different means. This separation can for example be realized:
  • the method according to the present invention is composed of the following steps:
  • Each partition supports a different IFW.
  • Each partition is allocated a set of LS codes as the orthogonal spread code
  • At least two partitions are allocated different sets of LS codes with different code lengths.
  • LA code Large Area code
  • PCT/CN98/00151 invented by Li Daoben and entitled "A Spread Spectrum Multiple Access Coding Method”
  • the present invention utilizes the LA code as described in PCT/CN98/00151 such that each SF carries a (136, 17, 2259) LA code.
  • This LA code consists of 17 pulses with a period of 2559 chips.
  • Each LA pulse corresponds to a time-slot within the SF.
  • the first time-slot may be used as the Pilot and the remaining 16 time-slots can be used for carrying user data or signaling information.
  • Figure 2 shows a LA code with 17 pulses.
  • the said partitions are sub-frames in the time domain, the number of sub-frame in each frame can be determined by the periodicity of selected LA codes.
  • the said sub-frame is divided into a plurality of time slots, in which the number of the said time slots can be determined by the number of pulses of the said LA codes, and the said time slot length varies with the variation of the pulse interval of the said LA codes.
  • the said LS codes fill the said time slot by modulation.
  • LAS-CDMA so that this allocating scheme could be referred to more easily.
  • LAS-CDMA is a wireless air interface allocating scheme that combines the benefits of CDMA and TDMA, two of the most popular wireless multiple access technologies in use today.
  • LAS-CDMA employs a new coding technique that reduces the interference among users, and thus resulting in higher user capacity and better quality.
  • LAS-CDMA employs a transmission frame structure similar to those used in TDMA based systems. This allows efficient allocation of bandwidth resources and QoS management that is desirable for supporting high-speed and variable rate data services.
  • each frame consists of N (e.g. 24576 in the case of LAS-2000) chips and is divided into M (e.g. 10 for LAS-2000) Sub-Frames (SFs).
  • the first Sub-Frame, SFO consists of NO (e.g. 1545 chips for LAS-2000) and it can be used for carrying control channels.
  • Figure 1 shows the LAS-2000 frame structure as a preferred embodiment of the present invention, and demonstrates how the frame is further divided into sub frames and time slots.
  • LAS-2000 is an operation mode of LAS-CDMA and the LS coded wireless systems, that is compatible with the IS-2000 standard.
  • the downlink channel of a LAS-2000 system consists of consecutive 20 ms frames.
  • SFO can be used as the Broadcast and Synchronization Channel (BSCH) in the downlink and as the Access Channel (ACH) in the uplink.
  • BSCH Broadcast and Synchronization Channel
  • ACH Access Channel
  • Each of these SFs consists of 2559 chips and is further divided into 17 time- slots.
  • the LS code is made up of two components, the S and C components, of equal length.
  • both the S and C components are 64 chips long.
  • the S and C components and are separated by a 4 chips gap.
  • Each LS code carries one modulation symbol.
  • the combined LA and LS code is called the LAS code.
  • Figure 3 shows the relation between the LA pulse and the LS code within a given time-slot.
  • Packet data traffic is differentiated from circuit based traffic, such as voice, in a number of aspects.
  • voice traffic generates a constant rate data stream, while the data rate and arrival pattern of packet data traffic is highly variably.
  • a packet data session that supports real-time traffic, such as voice conversation requires a constant bit rate connection, with low latency and delay variation.
  • packet data session that supports file download requires relatively high data rate with low bit error rate, while latency is not a major concern.
  • packet data arrivals follow an intermittent on and off pattern. During a packet data session, burst of data arrival is followed by a silent period. This alternating on and off cycle continues until the data session terminates.
  • This data arrival model has a significant impart on the design of channel allocation protocol. The channel allocation must be flexible and dynamic enough to support a wide range of data rates and, at the same time, allows the dynamic reallocation of resource such that multiplexing gain can be achieved.
  • This invention provides a method for supporting packet data traffic in a LS coded wireless system, such that variable data rate, up to the LS coded system limit, can be allocated to each users.
  • the method allows the sharing of codes and partitions (sub frames in the time domain) among a number of users. This results in multiplexing gain and provides in higher throughput and capacity.
  • one approach is to support LS codes of different code length within the same SF.
  • Another approach is to support the flexible allocation of the SF and LS codes on a per user basis. This invention provides a method that supports both approaches.
  • Figure 4 shows the LS code generation tree.
  • the originator At the root of the tree, there is a pair of 2-chip LS codes, called the originator. This originator is used for generating longer LS codes base on the LS code generation method as described in PCT application PCT/CNOO/00028.
  • the length of the LS code as well as the number of LS codes double.
  • Figure 4 clearly demonstrates the number of LS codes and their lengths at each level of the tree. Note that in the current implementation, the lowest level of the tree contains 128 LS code of length 128 chips. Since each LS code is used to spread a modulation symbol, the shorter the LS code, the larger the number of LS codes that can be sent within a fixed size time- slot, and thus the higher the data rate.
  • each LS code is positioned next to an LA pulse.
  • This LA pulse and the LS code constitute a time-slot within the frame structure.
  • multiple LS codes can be placed next to the LA pulse.
  • each time-slot now contains a pulse from the original LA code and M-1 shifted versions of the pulse.
  • M copies of the same LS coded can be placed in the time-slot as demonstrated in Figure 6.
  • the capacity of the LS code is increased by M time compared to the case when the time-slot carries only one LS code.
  • the number of LS codes per time- slot, M depends on the length of the LS code. In the preferred embodiment, given that the maximum length LS code that can be carried by a time-slot is 128 chips, M is equal to 128 divided by the length of the LS code. For LS code of length 128, one LS code (one C and one S component) can be carried by the time-slot. For LS code of length 32, four LS codes (four C and four S components) can be carried by the time- slot, and so on.
  • Figure 7 shows an example time-slot that carries eight 8-chip long LS codes.
  • the number of LS codes is reduced as the length of the LS code decreases.
  • the sub-free under the vertex is not used.
  • vertex X is the least common ancestor of sub-tree A.
  • sub-free A the remaining LS codes below vertex X within the same sub-free (sub-free A) cannot be used.
  • the other sub-frees such as subtree B, are not affected and can still be used.
  • any LS code in the tree can be used as long as none of its ancestors has been used. This means that any LS code can be selected from the free and be used for spreading modulated data traffic as long as none of the ancestors of the selected LS code has been used.
  • Each SF can support multiple LS codes with different lengths.
  • Different SFs with the frame structure can be configured differently and support a different set of LS codes. This enables high flexibility in radio resource and data rate allocation among multiple mobile terminals. This will be demonstrated in the following examples.
  • Figure 9 shows one example configuration of the LAS-2000 channels.
  • the carrier is set up to support 64 128-chip LS code channel, 16 64-chip LS code channels, and 8 32-chip LS code channels.
  • all SFs are configured in the same way such that each LS code forms a continuous channel.
  • each LS code of length 128, 64 and 32 chips form channels with throughput of 259.2Kbps, 518.4 Kbps, and 1036.8 Kbps, respectively.
  • each user can be assigned smaller number of SFs within the 20 ms frame.
  • the throughput per SF for 128, 64, and 32 chip LS codes are 28.8, 57.6, and 115.2 Kbps, respectively.
  • a mobile terminal can be allocated LS codes 1 and 2 in SF 4, 5, and 6, only.
  • the allocation can be for one particular 20 ms frame or for an extended duration.
  • multiple users may share the same allocation.
  • a data pipe can be carried by LS codes 1 and 2 in SFs 1 to 9. A number of mobile terminals may be assigned to this same data pipe. Multiple accesses with this data pipe can be achieved by explicit or piggybacked signaling.
  • Different symbol rates can be supported by using LS codes of different lengths.
  • One remote unit can be allocated one or more LS code and for each allocated LS code, one or more time slots or sub-frames.
  • Table 1 shows the modulation symbol rates and data rates when 16 QAM modulation is used per time slot per LS code and per sub- frame per LS code.
  • the present invention introduces an enhanced 16QAM, whose state diagram is illustrated in FIG. 13.
  • Other modulations such as QPSK can also be used.
  • the SFs can be grouped into larger units call Data Frames (DF).
  • DF Data Frames
  • Each DF can be used to carry one higher layer data block, such as a radio link layer frame.
  • Figure 11 shows an example where three SFs are combined together to form a DF.
  • Figure 11 shows only one of the possible configurations.
  • the number of SFs per DF can range from 1 to the maximum number of SFs per frame.
  • the configuration for each DF can be different.
  • Figure 12 shows an example wherein DF1, which consists of SF1, SF2, and SF3, supports 32 128-chip LS code channels, 16 64- chip LS code channels, and 16 32-chip LS code channels.
  • DF2 which consists of SF4, SF5, and SF6, supports 32 128-chip LS code channels, and 48 64-chip LS code channels.
  • DF3 which consists of SF7, SF8, and SF9, supports 128 128-chip LS code channels.
  • a mobile terminal can be allocated a given number of LS codes within a selected set of DFs. In addition, a number of mobile terminals may share a given allocation.
  • Figure 12 shows another example where circuit-based traffic, such as voice calls, and packet data traffic are supported simultaneous within the LAS-2000 frame structure. It is demonstrated in Figure 12 that the first 64 128-chip LS codes are assigned for circuit-based service. Each of these 64 LS codes is divided in the time domain into two channels. The first channel is made up of SF1 to SF4 and the second channel is made up of SF6 to SF9. SF5 is used to carry the dedicated control channels. According to this configuration, the LAS-2000 carrier supports 128 simultaneous voice calls. In addition, the LAS-2000 carrier as shown in Figure 12 also supports 4 16-chip LS codes and 8 32-chip LS codes.
  • These 12 LS codes are divided in the time domain into three data frame carriers that occupy SF1-SF3, SF4-SF6, and SF7-SF9, respectively.
  • This LS codes can be used to carry link layer frames for a number of packet data sessions.
  • a mobile terminal can be dynamically assigned a number of data frame carriers within selected LS codes when link layer frames are available for transmission. This allows the support of variable data rates. As mobile terminals are assigned data frame carriers only when needed, this allows the network to realize multiplexing gain due to the intermittence behavior of packet data traffic.
  • This example demonstrates how circuit-based service, such as voice, and packet data service can be supported within the same carrier.
  • the example given in Figure 12 represents one of the preferred embodiments. Other configurations that support various mixtures of voice and data fraffic and that utilize different LS code combinations are possible and are not shown in this example.
  • the interference reduction properties of LS coded wireless system resolve the power management challenge caused by the co-existence of time sensitive fraffic such as voice with best effort bursty fraffic of packet data services such as wireless Internet browsing or file or e-mail transfer.

Abstract

l'invention concerne un procédé pour l'interface aérienne de façon à supporter un débit de données variable, dans lequel l'interface aérienne est divisée en plusieurs partitions soit dans le domaine temporel, le domaine spatial, le domaine de fréquence, ou dans tout combinaison de ces domaines, chaque partition se voyant attribuer un ensemble de codes LS en tant que code par étalement orthogonal, différents ensembles de codes LS avec des longueurs de code différentes étant attribués à au moins deux partitions. L'utilisation de différentes longueurs de codes LS dans différentes partitions, et l'attribution souple de partitions différentes à chaque terminal mobile permettent d'obtenir le débit de données variable recherché de l'invention. Dans le domaine temporel, le procédé est réalisé par l'utilisation de différentes longueurs de codes LS, dans différentes sous-trames (SF) ainsi que part l'attribution souple de sous-trames à chaque terminal mobile.
EP00934846A 2000-06-05 2000-06-05 Procede pour l'interface aerienne de fa on a supporter un debit de donnees variable Withdrawn EP1303997A4 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2000/000139 WO2001095644A1 (fr) 2000-06-05 2000-06-05 Procede pour l'interface aerienne de façon a supporter un debit de donnees variable

Publications (2)

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EP1303997A1 EP1303997A1 (fr) 2003-04-23
EP1303997A4 true EP1303997A4 (fr) 2004-04-28

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CN (1) CN1193627C (fr)
AU (1) AU5057900A (fr)
WO (1) WO2001095644A1 (fr)

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Publication number Priority date Publication date Assignee Title
KR100474890B1 (ko) * 2000-11-27 2005-03-08 엘지전자 주식회사 엘에이에스（ｌａｓ）코드분할 다중접속 시스템에서의데이터 전송 방법
KR100705925B1 (ko) * 2000-11-28 2007-04-11 엘지전자 주식회사 라스 코드분할다중접속 확산 방법
US6714526B2 (en) * 2000-12-15 2004-03-30 Qualcomm Incorporated Method and apparatus for code assignment in a spread spectrum wireless communication system
KR100782204B1 (ko) * 2000-12-29 2007-12-05 엘지전자 주식회사 엘에스부호 선택에 따른 부호쌍 생성및 부호 할당 방법
KR100705924B1 (ko) * 2000-12-29 2007-04-11 엘지전자 주식회사 큐엘에스부호 선택에 따른 부호쌍 생성 및 부호 할당 방법
CN1613221A (zh) * 2002-03-11 2005-05-04 连宇通信有限公司 一种构建td－las系统的方法及装置
US8213489B2 (en) * 2005-06-23 2012-07-03 Agere Systems Inc. Serial protocol for agile sample rate switching
CN101159975B (zh) * 2006-09-22 2011-07-06 华为技术有限公司 一种空口资源分配指示方法、装置和用户终端

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EP0680168A2 (fr) * 1994-04-28 1995-11-02 AT&T Corp. Système et méthode pour optimaliser l'efficacité spectrale en utilisant une répartition en temps-fréquence et code
WO2000005831A1 (fr) * 1998-07-20 2000-02-03 Telefonaktiebolaget Lm Ericsson (Publ) Etaleur pour debits binaires multiples

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Title
See also references of WO0195644A1 *
WG1 OF CWTS: "LAS CDMA Presentation", 3GPP RAN WG1, 10 April 2000 (2000-04-10) - 14 April 2000 (2000-04-14), Seoul, Korea, pages 1 - 27, XP002242121 *

Also Published As

Publication number Publication date
CN1452843A (zh) 2003-10-29
EP1303997A1 (fr) 2003-04-23
WO2001095644A1 (fr) 2001-12-13
CN1193627C (zh) 2005-03-16
AU5057900A (en) 2001-12-17

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