Orthogonal Resource Hopping Based Mobile(Wireless) Communications (직교자원도약 기반 이동통신(무선) 통신)

Summary: We proposed a new concept called a ‘virtual dedicated’ resource allocation (VDRA) scheme based on orthogonal resource hopping. Orthogonal resources here mean frequency (sub)carriers, time slots, orthogonal codewords, phase, polarization, antenna space, etc. As a generalized form, we proposed a multi-dimensional orthogonal resource hopping multiplexing/multiple access (MD-ORHM(A)) in which resource blocks are allocated to each user, based on a user-specific pre-allocated hopping pattern before call(session) setup in downlink/uplink, respectively. The effects of this proposed MD-ORHM(A) scheme include 1)achieving a statistical multiplexing gain; 2)accommodating a larger number of users than the number of orthogonal resources; 3) significant reduction or removal of signaling overhead; 4) uniform resource utilization; and 5) interference mitigation.

1  Orthogonal Resource Hopping Based Multiplexing/Multiple Access Schemes: ORHM/ORHMA

• Downlink: (Multi-Dimensional)-Orthogonal Resource Hopping Multiplexing

• Uplink:  (Multi-Dimensional)-Orthogonal Resource Hopping Multiple Access

Motivation of This Work?

•   ‘Always-on’ internet services are available in wired networks. Why not in wireless networks?

•   Is it possible to provide ‘always-on’ internet services in wireless networks?

•   How to achieve minimum signaling overhead, large statistical multiplexing gain, accommodating a larger number of users with low activity bursty data, and virtual dedicated resource allocation?

Orthogonal Resources?

• Frequency (Sub)carriers, Time Slots, Phase, Orthogonal Codewords, Polarization, Antenna Space, etc

Why Orthogonal Resource Hopping?

•   To achieve statistical multiplexing

•   To accommodate a larger number of users than the number of orthogonal resources

•   To significantly reduce or remove signaling overhead during session

•   Uniform resource utilization

•   Interference mitigation, etc

Classification of Conventional Dedicated Resource Allocation Schemes in Our Terminology: (Refer to Fig. 1)

1)  One-Dimensional Orthogonal Resource Division Multiplexing (OD-ORDM) (our terminology)

•   FDM(Frequency Division Multiplexing)

•   TDM(Time Division Multiplexing)

•   CDM(Code Division Multiplexing)

•   OFDM(Orthogonal Frequency Division Multiplexing), etc

2)  One-Dimensional Orthogonal Resource Division Multiple Access (OD-ORDMA) (our terminology)

•   FDMA(Frequency Division Multiple Access)

•   TDMA(Time Division Multiple Access)

•   CDMA(Code Division Multiple Access)

•   OFDMA(Orthogonal Frequency Division Multiple Access)

3)  Multi-Dimensional Orthogonal Resource Division Multiplexing (MD-ORDM) 

• OFCDM(Orthogonal Frequency and Code Division Multiplexing)

4)  Multi-Dimensional Orthogonal Resource Division Multiple Access (MD-ORDMA)

• MC DS-CDMA(Multi-Carrier Direct Sequence Code Division Multiple Access)

Figure 1: Conventional ORDM(Orthogonal Resource Division Multiplexing)

What is our Proposed MD-ORHM (Multi-Dimensional Resource Hopping Multiplexing) Scheme? (Refer to Fig. 2)

• •   A downlink multiplexing scheme which achieves statistical multiplexing

  •   A super set of conventional multi-dimensional orthogonal resource division multiplexing (MD-ORDM) schemes in which all resources are allocated in a dedicated manner. (Examples: FDM, TDM, CDM, OFDM, OFCDM, etc) The MD-ORDM is a very special hopping case of the MD-ORHM because the former occupies a fixed resource.

  •   Resource blocks(e.g. frequency subcarriers, orthogonal codewords, time slots) are allocated to each user, based on a user-specific pre-allocated hopping pattern before call(session) setup

  •   Hopping patterns are generated regardless of data bursts

  •   Resource blocks are allocated in a virtual dedicated manner. However, only the allocated resources are used by active users with data bursts.

  •   Signaling overhead is removed or significantly reduced during session

  •   Hopping pattern collisions may sometimes cause a contention in the same resource allocation

  •   Contentions in resource allocation can be resolved through perforation and synergy

  •   Large statistical multiplexing gain can be achieved for bursty data with low channel activity

  •   Low latency and small delay variations

  •   Adequate for low/medium data rate services

  •   Adequate for services with real-time constraints

  •   A generalized statistical multiplexing scheme for orthogonal downlink systems based on the hopping of multiple orthogonal resources

  •   Hybrid scheduling systems combined with the proposed MD-ORHM and scheduling schemes can be a practical solution for future mobile communication systems. In the proposed hybrid systems, low/medium rate services and real-time services can be accommodated by the proposed MD-ORHM scheme and non real-time data services can be accommodated by the scheduling scheme.

  •   Our proposed ORHM schemes: OCHM, Frame-level OCHM, OFCHM, etc 

Figure 2: Proposed MD-ORHM(Multi-Dimensional Orthogonal Resource Hopping Multiplexing)

What is our proposed MD-ORHMA(Multi-Dimensional Orthogonal Resource Hopping Multiple Access) Scheme?

• • •   An uplink multiple access scheme which can achieve statistical multiplexing using a virtual dedicated resource allocation

    •   Hopping pattern collisions can be handled in a different way

    •   The remaining features are similar to those of the proposed MD-ORHM in downlink

    •   Hybrid multiple access systems combined with the proposed MD-ORHMA and uplink scheduling schemes can be a practical solution for future mobile communication systems. In the proposed hybrid multiple access systems, low/medium rate services and real-time services can be accommodated by the proposed MD-ORHMA scheme and non real-time data services can be accommodated by the uplink scheduling scheme.

    •   Our proposed schemes: OCHMA, RFH-OFDMA, etc

Classification of Our Proposed Virtual Dedicated Resource Allocation Schemes Based on Orthogonal Resource Hopping (Refer to Fig. 3)

1)      One-Dimensional Orthogonal Resource Hopping Multiplexing(OD-ORHM)

•   OCHM(Orthogonal Code Hopping Multiplexing)

•   Frame-Level OCHM

2)     One-Dimensional Orthogonal Resource Hopping Multiple Access(OD-ORHMA)

•   OCHMA(Orthogonal Code Hopping Multiple Access)

•   RFH-OFDMA(Random Frequency Hopping OFDMA)

•   OTHMA(Orthogonal Time Hopping Multiple Access)

3)      Multi-Dimensional Orthogonal Resource Hopping Multiplexing (MD-ORHM)

•   MD-ORHM

•   ORBHM(Orthogonal Resource Block Hopping Multiplexing)

•   OFCHM(Orthogonal Frequency and Code Hopping Multiplexing)

4)       Multi-Dimensional Orthogonal Resource Hopping Multiple Access (MD-ORHMA)

•   MD-ORHMA

Figure 3: Our Newly Proposed ORHM(A) Schemes and Conventional ORDM(A) Schemes

What is our proposed OCHM (Orthogonal Code Hopping Multiplexing)?

•   One-dimensional ORHM, a super set of the conventional CDMA

•   Orthogonal codewords are changed every symbol according to a user-specific hopping pattern

•   Other characteristics are similar to those of MD-ORHM

Conventional CDMA vs. Our Proposed Orthogonal Code Hopping Multiplexing (OCHM)? (Refer to Figs. 4 and 5)

•   A hopping pattern fixed at an orthogonal codeword(One specific codeword) is allocated to each downlink CDMA user in the conventional CDMA system.

•   Orthogonal codewords are changed every symbol according to user-specific hopping pattern in OCHM systems.

Figure 4: Conventional CDMA(Code Division Multiple Access)

Figure 5: Proposed OCHM(orthogonal Code Hopping Multiplexig)

As a one-dimensional case, we proposed an orthogonal code hopping multiplexing/multiple access(OCHM/OCHMA) and have extensive theoretical analysis on the proposed OCHM/OCHMA system including capacity analysis, collision mitigation, LLR(log-likelihood ratio) conversion, synergy/perforation control, switched beam in OCHM, channel coding in OCHM, adaptive code rate, comparison among OCHM, quasi-orthogonal codes (QOS), and multi-scrambling code(MSC), capacity improvement in OCHMA, and frame-level OCHM. As further extensions of the proposed scheme, we proposed orthogonal block code hopping multiplexing (ORBHM), orthogonal frequency hopping multiple access (OFHMA), orthogonal frequency and code hopping multiplexing (OFCHM), hybrid FH-OFDMA system in UWB radio networks, orthogonal time hopping multiple access (OTHMA) system in impulse radio based UWB environments.

The proposed MD-ORHM(A) scheme yields a statistical multiplexing gain with small signaling overhead and low latency, and it is efficient for low/medium data and real-time traffic(VoIP, gaming, machine-to-machine(M2M),etc). On the other hand, although the conventional scheduling schemes yield high throughput and multi-user diversity, they require large signaling overhead and, thus, they are inefficient for low/medium rate traffic and real-time traffic. They are very effective for data applications like FTP. Since each scheme has merits and demerits, we proposed a hybrid scheduling scheme in downlink and a hybrid multiple access scheme in uplink for future mobile communication networks. The proposed hybrid scheduling scheme consists of the proposed virtual dedicated resource allocation scheme called MD-ORHM(or its variation) and a scheduling scheme in downlink. The proposed hybrid multiple access scheme combines the proposed MD-ORHMA (or its variation) and a scheduling scheme in uplink. In these downlink/uplink hybrid scheduling schemes, the whole orthogonal resources are divided into two regions and allocated to both the MD-ORHM(A) scheme and the scheduling scheme. The MD-ORHM(A) scheme accommodates real-time and low/medium rate services, while the scheduling scheme accommodates high rate data services. Based on this research, our team presented a contribution on ‘Hybrid Multiple Access for IEEE 802.16m and Its Frame Structure’ in IEEE 802.16m standard meeting in Jan. 2008.

Comparision of Our Virtual Dedicated RA Scheme with the Dedicated and Scheduling RA Schemes:(Refer to Fig. 6)

We propose a virtual dedicated resource allocation scheme based on ORHM(A). Figure 6 compares our virtual dedicated RA(random accesss) scheme with the dedicated (2G CDMA) & scheduling RA schemes. 

Figure 6: Comparision of Our Virtual Dedicated RA Scheme with the Dedicated and Scheduling RA Schemes

Proposed Hybrid Resource Allocation Scheme: (Refer to Fig. 7)

We propose the following Hybrid Multiplexing/Multiple Access Schemes combined with our virtual dedicated resource allocation scheme and the scheduling-based resorce allocation scheme.

Figure 7: Our Proposed Hybrid Multiplexing/Multiple Access Scheme

Major Achievements in our proposed ORHM(A) Schemes?

• •   Proposed OCHM scheme

  •   Log-Likelihood Ratio(LLR) conversion schemes in OCHM

  •   Collision mitigation by LLR conversion in OCHM

  •   Capacity improvement in CDMA downlink with OCHM

  •   Switched beam in OCHM

  •   Adaptive Beamforming Antennas in OCHM(patent)

  •   Effect of channel coding in OCHM

  •   Synergy/perforation control for 16QAM in OCHM

  •   Performance Analysis of OCHM

  •   Performance Comparison between OCHM and HDR(high Data Rate)

  •   Adaptive Code Rate in OCHM

  •   Multi-rate Transmission in OCHM

  •   Symbol Repetition and Power Reallocation in OCHM

  •   Performance Comparison between OCHM and Multi-scrambling Code(MSC)

  •   Capacity Analysis of CDMA with Quasi-Orthogonal Sequences(QOS)

  •   Orthogonal pre-spreading in OCHM

  •   Capacity Improvement with uplink OCHMA

  •   Frame-level OCHM

  •   Throughput Analysis of downlink scheduling systems

  •   Hopping pattern based resource allocation in the Mobile WiMAX System

  •   OTHMA(Orthogonal Time Hopping Multiple Access) Scheme in a UWB environment (paper, patent)

  •   Hybrid FH-OFDMA System in OFDM based UWB indoor radio access networks

  •   OFHMA(Orthogonal Frequency Hopping Multiple Access) System (patent)

  •   ORBHM(Orthogonal Resource Block Hopping Multiplexing) System(patent)

  •   OFCHM(Orthogonal Frequency and Code Hopping Multiplexing) System (patent)

  •   Performance Analysis of Orthogonal Frequency and Code Hopping Multiplexing(OFCHM)

  •   MD-ORHM(Multi-Dimensional Orthogonal Resource Hopping Multiplexing) System (Patent)

  •   Digital Communication System based on MD-ORHM(patent)

  •   Collision Mitigation in MD-ORHM (patent)

Awards for the Related Work

•   ‘Top Scientist of the Month’ Award for contribution to the development of ‘Multi-Dimensional Orthogonal Resource Hopping Multiplexing(MD-ORHM) Schemes’, awarded by the Ministry  Science and Technology (MOST) and Korea Science & Engineering Foundation (KOSEF), May 2004.(One top scientist/engineer is awarded every month among all science and engineering fields)

International Standard Activity (IEEE 802.16m)

•   B.C. Jung, J. Kim, M.S. Kang, S. Kim, D.K. Sung, Hybrid Multiple Access for IEEE 802.16m and Its Frame Structure, Contribution IEEE C802.16m-08/027, Finland, Jan. 2008.

ORHM-Related Journal Papers

• Y.I. Seo and D.K. Sung,  “Virtually Dedicated Resource Allocation for VoIP Traffic in the Downlink Mobile WiMAX System with Hybrid ARQ,” IEEE Transaction on Vehicular Technology, vol.60, no. 2, pp.514-527, Feb. 2011.

-          Main contributions:

• • •   The virtually dedicated resource allocation scheme based on our proposed orthogonal resource block hopping multiplexing(ORBHM) is proposed to significantly reduce signaling overhead for accommodating low/medium data traffic, including real-time VoIP traffic in mobile WiMAX system.

    •   The proposed scheme yields a 15%-28%icrease in user capacity and a 26%-69% decrease in the size of signaling overhead compared with the dynamic scheduling scheme.

    •   The applicability of the proposed scheme can be extended to periodic and non-periodic traffic , as well as real-time and non-real-time traffic.

•  B.C. Jung, S.S. Cho, D.K. Sung,  “Uplink Capacity Improvement Through Orthogonal Code Hopping in Uplink-Synchronized CDMA Systems,” IEEE Transaction on Wireless Communications, vol. 8, no. 11, pp.5404-5410, Nov. 2009.

-          Main contributions:

• • •   For the first time, OCH concept is applied to uplink-synchronized CDMA systems

    •   Performance comparison between OCH- and MSC-based CDMA uplink

    •   Optimal receiver design is proposed for OCH-based CDMA uplink systems

• S. H. Moon, S. Park, J.K. Kwon, J. Kim, D.K. Sung, “Group Mode Hopping for Collision Mitigation in Orthogonal Code Hopping Multiplexing,” IEEE Trans. On Vehicular Technology,” vol. 58, no.7, pp.3830-3834, Sep. 2009.

-           Main contributions:

• • •   Collision-free group concept is proposed for collision mitigation in OCHM

    •   Performance gain in terms of the additionally required Eb/No and system capacity

• B.C. Jung, S.S. Cho, D.K. Sung, “Performance Comparison of Downlink Capacity Improvement Schemes: Orthogonal Code Hopping Multiplexing vs. Multiple Scrambling Codes,” IEEE Trans. on Vehicular Technology, vol. 58, no. 2, pp.670-681, Feb. 2009.

-          Main contributions:

• • •   Capacity comparison between the OCHM and MSC systems

    •   Qualitative and quantitative performance comparisons between OCHM and MSC systems

• 5.       B.C. Jung, D.K. Sung, “Performance Analysis of Orthogonal Code Hopping Multiplexing Systems with Repetition, Convolutional, and Turbo Coding Schemes,” IEEE Trans. On Vehicular Technology, vol. 57, no.3, pp.932-944, March 2008.

-          Main contributions:

• • •   Rigorous mathematical analysis of BER performance of OCHM system

    •   User capacity estimation of OCHM system based on the BER performance analysis

• S.H. Moon, J. Kim, D.K. Sung, “Performance Analysis of Orthogonal Frequency and Code Hopping Multiplexing,” IEEE Trans. on Wireless Communications, vol. 6, no. 10, pp.3803-3815, Oct. 2007.

-          Main contributions:

• • •   Multi-dimensional resource hopping for next-generation wireless communication systems

      •   Frequency & Code

    •   Performance comparison between OFCHM and OFCDM (NTT DoCoMo)

    •   The OFCHM yields better performance than the scheduling system in packet delay, packet delay variance, and fairness, and has a system throughput advantage with low/medium rate services. The significance of this result is to need a hybrid scheduling system combining a virtual dedicated resource hopping scheme and a scheduling scheme to accommodate variable data rates and QoSs.

• S.H. Moon, J.K. Kwon, D.K. Sung, “Synergy/Perforation Control for 16QAM in Orthogonal Code Hopping Multiplexing,” IEEE Trans. On Vehicular Technology, vol. 56, no.4, pp.1704-1715, July, 2007.

-          Main contributions:

• • •   New synergy/perforation control scheme for hopping pattern collisions in 16QAM

    •   Applying OCHM to high modulation schemes - Bandwidth efficient OCHM system

• J.W. Chong, B.C. Jung, D.K. Sung, “Statistical Multiplexing Based Hybrid FH-OFDMA System for OFDM-Based UWB Indoor Radio Access Networks,” IEEE Trans. On Microwave Theory and Techniques, vol. 54, no. 4, pp. 1793-1801, April, 2006.

-          Main contributions:

• • •   Applying the orthogonal resource hopping concept to OFDM-based UWB networks

    •   User capacity improvement in unlicensed band using the ORHM concept

    •   The proposed HFH-OFDMA can accommodate 256 users, while the conventional FH-OFDMA system accommodates 50 users when the user channel activity is 0.1 in a piconet UWB environment. Here, the system capacity is limited by either the total number of available subcarriers in a piconet(resource-limited) or the FCC UWB emission limit(power-limited). The result shows a significant increase in the capacity.

• J.K. Kwon, S. Park, D.K. Sung, “Collision Mitigation by Log-Likelihood Ratio (LLR) Conversion in Orthogonal Code Hopping Multiplexing,” IEEE Trans. on Vehicular Technology, vol. 55, no. 2, pp.709-718, March 2006.

-          Main contributions:

• • •   Reducing the effect of the HP collision in OCHM systems

    •   LLR conversion schemes to significantly reduce the required Eb/No by up to 10dB  in channel coding even when the perforation probability is high.

    •   Optimal receiver design for OCHM systems

• S.H. Moon, S. Park, J.K. Kwon, D.K. Sung, “Capacity Improvement in CDMA Downlink with Orthogonal Code Hopping Multiplexing,” IEEE Trans. on Vehicular Technology, vol. 55, no. 2, pp.510-527, March 2006.

-          Main contributions:

• • •   Downlink capacity analysis of OCHM systems

    •   Maximum number of users in a cell for a given channel code

• J.H. Chung, S. Park, D.K. Sung, “Symbol Perforation Reduction Schemes for Orthogonal Code Hopping Multiplexing,” IEICE Trans. On Communications, vol. E88-B, no. 10, pp.4107-4111, October 2005.

-          Main contributions:

• • •   Applying the switched beam array antenna for reducing the effect of HP collision on system capacity

    •   User capacity improvement through multiple antennas techniques

• J.K. Kwon, S. Park, D.K. Sung, “Log-Likelihood Ratio (LLR) Conversion Schemes in Orthogonal Code Hopping Multiplexing,” IEEE Communications Letters, vol. 7, no. 3, pp.104-106, March 2003.

-          Main contributions:

• • •   Reducing the effect of the HP collisions through  LLR re-computation at the receiver of  OCHM systems

    •   Optimal receiver design for a given perforation probability

• S.Park and D.K.Sung, “Orthogonal Code Hopping Multiplexing, IEEE Communications Letters, vol. 6, no. 12, pp.529-531, Dec. 2002.

-          Main contributions:

• • • •   For the first time, a statistical multiplexing concept is applied to CDMA cellular downlink.

      •   Capacity improvement in code-limited situation in CDMA downlink

      •   The number of downlink orthogonal channels can be supported more than the number of orthogonal codewords in the orthogonal code.

      •   With 64 orthogonal codewords, more than 300 downlink orthogonal channels can be supported if their average channel activity is smaller than 0.1. This is a very significant result.

ORHM-Related International Conference Papers

• T.S. Choi, S.H. Kim, and D. K. Sung, “Block Scheduling for Low-rate, Real-Time Traffic in Downlink Mobile WiMAX System,” IEEE WCNC 2011, April 2011.

• S.M. Kim, B.C. Jung, J.W. Chong, C.Y. Jung, D.K. Sung, “Capacity Analysis of a TH-PPM UWB System Using a Near-Interference Erasure Scheme in Multi-User Environments,” IEEE PIMRC 2007, Sep. 2007.

• C.W. Ryu, B.C. Jung, S.H. Moon, D.K. Sung, “Distance-Based Code-Collision Control Scheme Using Erasure Decoding in Orthogonal Code Hopping Multiplexing,” ICACT 2007, Feb. 2007.

•  B.C. Jung, S.S. Cho, D.K. Sung, “Downlink Capacity Improvement through Orthogonal Code Hopping Multiplexing and Multiple Scrambling Codes in CDMA Systems,” IEEE Globecom 2006, November 2006.

• S.S. Cho, B.C. Jung, D.K. Sung, “Capacity Analysis of Downlink CDMA Systems with Quasi-Orthogonal Sequences,” IEEE Globecom 2006, November 2006.

• M.J. Kim, B.C. Jung, J.W. Chong, D.K. Sung, “Performance Enhancement of a TH-PPM UWB System Using a Near-Interference Erasure Scheme in Multi-User Environments,” IEEE Int. Conference on UWB, September 2006.

• B.C. Jung, D.K. Sung, H. Jin, S.Y. Chung, “ Performance Analysis of Orthogonal Code Hopping Multiplexing Systems,” IEEE ICC 2006, June 2006.

• S.H. Moon, H.J. Lee, J. Kim, J.K. Kwon, D.K. Sung, “Multi-Rate Transmission in Orthogonal Code Hopping Multiplexing,” APCC 2005, Oct. 2005.

• C.Y. Jung, Y.J. Hong, B.C. Jung, D.K. Sung, “Orthogonal Time Hopping Multiple Access for UWB Impulse Radio Communications,” APCC 2005, Oct. 2005.

• J.W. Chong, B.C. Jung, J.H. Chung, D.K. Sung, “Statistical Multiplexing Based Hybrid FH-OFDMA System for OFDM-Based UWB Indoor Radio Access Networks,” IEEE Int. Conference on Ultra-Wideband, Sep. 2005.

• M.J. Kim, J.H. Chung, C.Y. Jung, J.W. Chong, D.K. Sung, “Link Performance Evaluation of a TH-PPM UWB System in the Presence of Multi-User Interference,” IEEE Int. Conference on Ultra-Wideband, Sep. 2005.

• Y. Seo and D.K. Sung, “A Novel Frame Level Orthogonal Code Hopping Multiplexing Scheme,” IEEE ICC 2005, May 2005.

• B.C. Jung, D.K. Sung, “Random FH-OFDMA System Based on Statistical Multiplexing,” IEEE VTC 2005 Spring, May 2005.

• S.H. Moon, J.K. Kwon, D.K. Sung, “Frame Level Control for Collision Mitigation in Orthogonal Code Hopping Multiplexing,” IEEE WCNC 2005, March 2005.

• B.C. Jung, J.H. Chung, D.K. Sung, “Symbol Repetition and Power Reallocation Scheme for Orthogonal Code Hopping Multiplexing Systems,” APCC/IEEE PIMRC 2004, pp.80-84, Sep. 2004.

• J. Kim, S.H. Moon, D.K. Sung, “Framework for Multirate Transmission in Orthogonal Code Hopping Multiplexing,” APCC/MDMC 2004.

• J.K.Kwon, S.Park, D.K.Sung, H.S.Lee, “Adaptive Code Rate for Orthogonal Code Hopping Multiplexing(OCHM) in Synchronous Downlink,” WCNC’03, pp.855-859, 2003.

• S.Park,  S.H.Moon, J.K.Kwon, D.K.Sung, “Orthogonal Code Hopping Multiplexing for Downlink Statistical Multiplexing,” IEEE Symposium on Spread Spectrum Tech. & Applications (ISSTA) 2002, pp.582-592, 2002.

• J.K.Kwon, S.Park, D.K.Sung, “Performance Comparison of Orthogonal Code Hopping Multiplexing(OCHM) and HDR Schemes in Synchronous Downlink,” WCNC 2002, pp.200-205, 2002.

• S.Park, D.K.Sung, “Orthogonal Code Hopping Multiplexing for Downlink in Spread Spectrum Communications,” MDMC 2001, 2001.

ORHM/ORHMA Related Patents

3 Key Patents:

• Patent: S.W.Park, D.K.Sung, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,”7,349,447, USA, March 2008. (Also granted in Korea, Japan, Australia, China, India, Canada, France, UK, and Germany)

  • This patent was first filed in 1999 in Korea. This is the original patent describing a statistical multiplexing concept based on orthogonal code hopping multiplexing (OCHM). OCHM is also named by the inventors. The conventional CDMA is classified as a special cases of OCHM and OCHM is the generalization of the conventional downlink multiplexing based on orthogonal code channel. This patent was transferred to ETRI. From this patent, 53 patents, 13 journal papers, 18 conference papers, one IEEE802.16m contribution, 8 Ph.D and 6 M.S. degrees were produced.

•  Patent: S.Park, D,K,Sung, “Multi-dimensional Orthogonal Resource Hopping Multiplexing Communications Method and Apparatus,” 7,149,199, USA, Dec. 12, 2006.(Also Granted in Korea, Canada, Japan, India, Australia, and China; Pending in EU)

• • This patent describes statistical multiplexing based on multi-dimensional orthogonal resource hopping multiplexing (MD-ORHM). MD-ORHM is also named by the inventors. All of the conventional multiplexing schemes in downlink, for example, OFDM can be classified as special cases of MD-ORHM. This patent technology was also transferred to ETRI. We have developed many new applications and variations from this patent technology, including Frame-level OCHM, Random Frequency Hopping(RFH)-OFDMA, Hybrid FH-OFDMA in UWB environments, Orthogonal Time Hopping Multiple Access(OTHMA) in Impulse Radio based UWB environments, Orthogonal Resource Block Hopping Multiplexing(ORBHM), and Orthogonal Frequency and Code Hopping Multiplexing(OFCHM), etc.

• Patent: S. Park, D.K. Sung, 14 more, “Method and Apparatus for Mitigating the Effect of Collision of Hopping Patterns in Multi-Dimensional Resource Hopping Multiplexing Communications,” 2002329101, Australia, Nov. 4, 2005.(Also granted in Japan; 5 split patents granted in Korea; pending in USA, EU, Canada, India, and China)

This patent is concerned with handling a hopping pattern collision problem inherently occurring in MD-ORHM. It includes hopping pattern detection mechanisms, collision resolution through synergy and perforation, and collision mitigation. This method can be widely applied to any ORH based systems. 

Patent List:

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S.W. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, and H.S. Lee, “ Digital Communication Method and System(디지털 통신 방법 및 그 시스템),” EP 1,890,392,  (Application number 07075296.9, filing Sep. 18, 2002, Priority KR 20010057421, (Sep. 18, 2001)), Aug. 12, 2015. 

•  J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S.W. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, and H.S. Lee, “ Digital Communication Method and System,” EP 1,890,391, (DE 602 47 287.3) (Application number 07075297.7, filing Sep. 18, 2002, Priority KR 20010057421, (Sep. 18, 2001)), July 1, 2015.

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S.W. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, and H.S. Lee, “ Digital Communication Method and System,” EP 1,921,756, (Application number 07075298.5, filing Sep. 18, 2002, Priority KR 20010057421, (Sep. 18, 2001)), July 1, 2015. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, and J.W. Chong, “Multiple Access Digital Communicating Method in Ultra-wideband Radio Access Networks,” US8588190 B2, U.S.A., (US 11/910,143, March 28, 2006), Nov. 19, 2013. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, and J.W. Chong, “Multiple Access Digital Communicating Method in Ultra-wideband Radio Access Networks,” EP1864408 A4, EU, (EP20060732719, March 28, 2006), May 1, 2013. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, J.W. Chong, “Multiple Access Digital Communication Method in Ultra-Wideband Radio Access Networks (초광대역 무선 접속망에서의 다중접속 방법),” JP5064377B2, Japan, (JP2008503943A (2006.03.28 application)), granted Oct. 31, 2012. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” EP1890392 A3, (EP20070075296, Sep. 18, 2002), March 28, 2012.

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” EP1890391 A3, (EP20070075297, Sep. 18, 2002), March 28, 2012.

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song,  I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System Using Multidimensional Hopping Patterns,” EP1921756 A3, (EP20070075298, Sep. 18, 2002), March 28, 2012. 

• D.K. Sung, S.H. Moon, B.C. Jung, J.H. Chung, Y.J. Hong, Y.I. Seo, J. Kim, “Orthogonal Frequency and Code Hopping Multiplexing Method and Apparatus,” US 8094547, USA,  Jan. 10, 2012. 

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• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song,  I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, , “Digital Communication Method and System,” CA2460790 C, Canada, ( CA 2460790, Sep. 18, 2002), August 10, 2010. 

• D.K. Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications(2),” 2494774, Canada, July 27, 2010. 

• D.K. Sung, S.H. Kim, S.M. Kim, S.H. Yoon, “Communication Method Using Statistical Multiplexing and Apparatus for Performing the Same,” US2010 0177687 A1, USA, (US 12/591, 859, Dec. 3, 2009), July 15, 2010. 

• S. Park, D.K. Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” DE60142230 D1, Germany, (DE2001642230, Feb. 6, 2001), July 8, 2010. 

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” US7738510 B2, USA, (US 10/490,566, Sep. 18, 2002), June 15, 2010. 

• S. Park, D.K. Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” EP1293056 B1, EU, (EP200010906365, Feb. 6, 2001), Nov. 15, 2002) May 26, 2010. 

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S..I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” DE60234460 D1, Germany, (DE2002634460, Sep. 18, 2002), Dec. 31, 2009. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” 1435140, Europe, Nov. 18, 2009.

• D.K. Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” DE60042452 D1, Germany, (DE200642452, Aug. 3, 2000), Aug. 6, 2009.  

• D.K. Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” EP1203468 B1, (EP20000948404, Aug. 3, 2000), UK, June 24, 2009. 

• D.K.Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” #1203468, UK, France, and Germany, June 24, 2009. 

• D.K.Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” #232400, India, March 16, 2009.

• S.Park, D,K,Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” #231902,  India, March 13, 2009. 

• D.K. Sung, J.H. Chung, S. Park, B.C. Jung, “Apparatus and Method for Applying Switched-Beam Array Antennas in Orthogonal Code Hopping Multiplexing Systems,” #10-0860537, Korea, Sep. 22, 2008. 

• D.K. Sung, J.H. Chung, S. Park, B.C. Jung, “Orthogonal Code Hopping Multiplexing Systems Employing Adaptive Beamforming Array Antenna (적응형 빔 형성 배열 안테나를 채용한 직교 부호 도약다중화 시스템 ),” 10-0860534, Korea, (1020060138359 (2006.12.29) ), Sep. 22, 2008. 

• S.Park, D,K,Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” #ZL00811360.2, China, Sep. 3, 2008. 

• D.K. Sung, J.H. Chung, S. Park, B.C. Jung, “Orthogonal Code Hopping Multiplexing Systems Employing Adaptive Beamforming Array Antenna,” #10-0860534, Korea, Sep. 22, 2008. 

• D.K. Sung, B.C. Jung, “Method and Apparatus of Transmitting and Receiving Digital Data Supporting Multiple Access (다중 접속을 지원하는 디지털 데이터 송수신 방법 및 장치),” 10-0850821, Korea, (1020060103948 (2006.10.25)), July 31, 2008. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, and J.W. Chong, “Multiple Access Digital Communicating Method in Ultra-wideband Radio Access Networks,” US2008 0165746 A1, USA, (US 11/910, 143, March 28, 2006), July 10, 2008. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, J.W. Chong, ”Multiple Access Digital Communication Method in Ultra-Wideband  Radio Access Networks,” #10-0835303, Korea, May 29, 2008. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, C.W. Chong, “Multiple Access Digital Communicating Method in Ultra-Wideband Radio Access Networks (초광대역 무선 접속망에서의 다중접속 디지털 통신방법),” 10-0829989, Korea, (1020060027882 (2006.03.28)), May 8, 2008. 

• S.Park, D.K. Sung, et al.,”Method and Apparatus for Mitigating the Effect of Collision of Hopping Patterns in Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications,” 4128957, Japan, May 23, 2008.

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S..I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee., “Digital Communication Method and System Using Multidimensional Hopping Patterns,” EP1921756 A2, EU, ( EP20070075298, Sep. 18, 2002), May 14, 2008.

• D.K.Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” 7349447, USA, Mar. 25, 2008. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” EP1890392,  EU, Feb. 20, 2008. 

• D.K. Sung, B.C. Jung, H.Y. Hwang, C.Y. Jung, Y.J. Hong, and J.W. Chong, “Multiple Access Digital Communicating Method in Ultra-wideband Radio Access Networks,”EP1864408 A1, EU, (EP20060732719, March 28, 2006), Dec. 12, 2007. 

• S.Park, D,K,Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” 2,409,192, Canada, Oct. 30, 2007. 

• S.Park, D.K.Sung, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” Patent No. 0755038, Korea, Aug. 28, 2007. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” Patent No. 0743556, Korea, July 23, 2007.

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System (디지털 통신 방법 및 그 시스템),” 10-0687078, Korea, (1020060067916 (2006.07.20) ),   Feb. 20, 2007. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” Patent No. 0660026, Korea, Dec. 14, 2006. 

• S.Park, D,K,Sung, “Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications Method and Apparatus,” 7,149,199, USA, Dec. 12, 2006. 

• D.K. Sung, S.H. Moon, B.C. Jung, J.H. Chung, Y.J. Hong, Y.I. Seo, J. Kim, “Orthogonal Frequency and Code Hopping Multiplexing Method and Apparatus,” 0654316, Korea Nov. 29, 2006. 

• D.K.Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications(1),” 2381304, Canada, Nov. 21, 2006. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” Patent No. 0644233, Korea, Nov. 2, 2006. 

• D.K. Sung, Y.I. Seo, B.C. Jung,, “Orthogonal Resource Block Hopping Multiplexing Method and Apparatus,” 0642361, Korea, Oct. 27, 2006. 

•  J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” US2006 0239334 A1, USA, (US 10/490,566, Sep. 18, 2002), Oct. 26, 2006.

• Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” 0641797, Korea, Oct. 26, 2006. 

• B.C. Jung, H.J. Lee, D.K. Sung, “Digital Communication Method Using Orthogonal Frequency Hopping Multiple Access Scheme in a Synchronized Uplink, Patent No. 0627937, Korea, Sep. 22, 2006. 

• S. Park, J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and the System,” Patent No. 0687078, Korea, Feb. 20, 2006. 

• D.K. Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” 3748853, Japan, Dec. 9, 2005. 

• S.Park, D.K. Sung, et al., “Method and Apparatus for Mitigating the Effect of Collision of Hopping Patterns in Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications,” 2002329101, Australia, Nov. 4, 2005. 

• S. Park, D.K. Sung, et al., “Method and Apparatus for Mitigating the Effect of Collision of Hopping Patterns in Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications,” 2002329101, Canada, Nov. 4, 2005. 

• D.K. Sung, S. Park, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” 2003244550, Canada, Aug. 26, 2005. 

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” EP1435140 A4, EU, (EP20020765679, Sep. 18, 2002), April 20, 2005. 

• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” CN1593018 A, China, (CN 02822777, Sep. 18, 2002), March 9, 2005.

• S.Park, D,K,Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,”3648562, Japan, Feb. 25, 2005. 

• S.Park, D,K,Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” 2001234199, Australia, Feb. 18, 2005. 

• J.K.Kwon, S.Park, D.K.Sung, H.S. Park, S.G. Lee, K.H. Chang, “Digital Communication System Based on Multi-Dimensional Orthogonal Resource Hopping Multiplexing,’ 448894, Korea, Sep. 6 2004. 

•  J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” EP1435140 A1, EU, (EP20020765679, Sep. 18, 2002), July 7, 2004. 

• S.Park, D.K.Sung, “Method and Apparatus for Orthogonal Code Hopping Multiplexing Communications,” No. 767200, Australia, Feb. 19, 2004. 

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• J.K. Kwon, K.S. Shin, J.H. Chung, J.Y. Yun, S.H. Moon, S.M. Park, D.K. Sung, S. Park, M.G. Kyeong, J.S. Cha, S.Y. Lee, S.I. Song, I.S. Sohn, J.P. Cho, J.J. Kim, H.S. Lee, “Digital Communication Method and System,” CA2460790, Canada, ( CA 2460790, Sep. 18, 2002), March 27, 2003. 

• S. Park, D.K. Sung, “Multidimensional Orthogonal Resource Hopping Multiplexing Communications,” EP1293056 A1, EU, (EP20010906365, Feb. 6, 2001), March 19, 2003.

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제안기술: 다차원직교자원도약다중화/다중액세스시스템 (Multi-dimensional Orthogonal Resource Hopping Multiplexing/Multiple Access Systems: MD-ORHM(A)) 기술

본 제안기술은 이동통신에서 사용가능한 직교자원은 (부)반송파(sub-carrier), 타임슬롯, 직교부호(Orthogonal codewords), 편광(polarization), 안테나 공간(space) 등을 포함하는데 호/세션이 설정단계에서 미리 이 직교자원의 조합을 이용한 다차원직교자원의 자원블록을 가입자별 할당된 도약패턴(hopping pattern)을 기반으로 시간상에 가입자에게 자원을 할당하고 이 할당된 자원을 이용하여 보내고자 하는 정보를 전달하는 다중화/다중액세스(multiplexing/multiple access) 기술로 MD-ORHM(A) 이라 지칭한다.

KAIST에서 독창적으로 제안하고 있는 MD-ORHM의 주요 특징은 통계적 다중화를 실현화는 하향링크 기술로서 기존 통신에서의 전용자원할당방식도 도약패턴의 하나의 특정한 사례이므로 제안한 자원도약할당은 기존의 통신방식을 같이 수용하는 일종의 ‘Super-set’이다. 도약패턴이 가입자에게 호/세션 설정 시 할당되는데 데이터의 버스트에 관계없이 자원블록이 할당되어 세션 중에 제어신호의 오버헤드가 거의 없거나 최소로 줄일 수 있는 장점이 있으며, 데이터가 있을 경우에 전송되어 일종의 통계적 다중화 이득을 얻을 수 있으며 저지연과 저지연변동의 성능을 가져 저속/중속 데이터 서비스이나 VoIP 같은 실시간 서비스에 적합하다. 또한 기존의 고속 데이터를 처리하는 스캐쥴링 방식과 제안하는 자원도약방식을 하이브리드 모드로 구성한 하이브리드 스캐쥴링 방식을 수용하면 고속과 저속 데이터를 보다 효율적으로 처리 가능하다. 지금까지 논문과 특허기술로 검증한 제안된 가상전용자원할당방식은 1차원 직교자원도약다중화 (OD-ORHM) 방식으로 직교부호도약다중화(OCHM)과 Frame-level OCHM 방식이 있으며, 다차원 직교자원도약다중화(MD-ORHM)방식으로 MD-ORHM, 직교자원블록도약다중화(ORBHM), 직교주파수부호도약다중화(OFCHM) 방식이 제안되고 있다.

MD-ORHMA 기술의 주요 특징은 가상전용자원할당방식으로 상향링크 상에서 통계적다중화 이득을 얻는 기술로 도약패턴 상의 충돌이 일어날 수 있지만 충돌 완화/해결방안이 연구되어 있고, 다른 특징은 MD-ORHM기술과 유사하며, 지금까지 논문이나 특허로 검증한 기술로는 1차원 직교자원도약다중액세스(OD-ORHMA) 방식인 직교부호도약다중액세스(OCHMA), 랜덤주파수도약(RFH) OFDMA, 직교시간도약다중액세스(OTHMA) 방식이 있으며 다차원 직교자원도약다중액세스(MD-ORHMA)도 제안되어 있다.

제안 시스템과 기존의 2,3,4,5 세대 통신에서의 자원할당방식과의 비교는 다음과 같다.

• 2G CDMA, GSM: 전용(dediced) 자원할당, 저지연, 낮은 채널효율, 실시간 음성 응용

• 3G, 4G, WiBro, 5G 시스템: 스캐쥴링 기반 자원할당, 고수율, 제어신호 오버헤드 과다, 실시간 트래픽 비효율, 저속/중속 트래픽 수용 비효율, 버스트 데이터 트래픽 적합

• 제안하는 ORHM(A) 기반 가상전용(virtually dedicated) 자원할당방식: 가입자별 도약패턴 기반의 자원블록 자원할당, 저지연, 최소의 제어신호 오버헤드, 통계적다중화 이득 실현, 고속 데이터 비효율, 실시간, 저속/중속 서비스 적합

핵심특허 3건 소개:

•  직교부호도약다중화 통신방식 및 장치 (Orthogonal Code Hopping Multiplexing Communications):직교부호도약다중화(OCHM)방식의 원천특허; 도약 패턴의 충돌처리 방법; 기술구현위한 심볼비교기 구조; 가변확산부호를 통한 직교부호다중화 통신방식; 다중도약패턴 할당방식

•  다차원 직교 자원 도약 다중화 통신 방식 및 장치(Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications Method and Apparatus thereof):다차원직교자원 도약 다중화 방식의 원천 특허; 다차원직교자원의 충돌 처리 방법; 다차원직교자원 발생기 구조; 중요도에 따라서 고정적 직교 자원군과 도약 다중화 자원군을 분리하여 운영하는 방법 등

•  다차원 직교 자원 도약 다중화 통신 방식에서 도약 패턴 충돌 영향 완화 방법 및 장(Method and Apparatus for Mitigating the Effect of Collision of Hopping Patterns in Multi-Dimensional Orthogonal Resource Hopping Multiplexing Communications): 다차원 직교 자원 도약 다중화 방식에서 충돌시 단말의 위치에 따른 천공 심볼의 처리 방법; 충돌시 성능 감소를 줄이기 위한 채널 코딩 방법; 충돌을 줄일 수 있는 무선 자원 관리 방법

13개 국제저널 논문 연구를 통하여 아래의 결과가 도출되었다.

•  평균 채널 활성도가 0.1 일 경우 64개의 직교부호로 300개의 하향 링크 지원 가능하여 통계적다중화 효과가 약 5배에 해당(통계적 다중화 효과)

•  OCHM 시스템에서의 수신기 LLR 재설계에 의해 도약패턴 상의 충돌 완화와 주어진 천공확률 기반 최적의 수신기 설계

•  도약패턴상의 충돌완화를 위한 스위치빔 어래이 안테나 적용을 통한 용량 중대

•  OCHM 시스템에서의 수용 가능한 가입자 용량 분석

•  OCHM 시스템에서의 도약패턴 충돌완화를 위한 LLR 변환방식의 제안과 최적 수신기 설계

•  OFDM 기반 UWB 망에 직교자원도약의 개념 적용하여 Hybrid FH-OFDMA 방식 제안하고 pico 망에서 채널 활성도가 0.1인 경우 256 가입자 수용 용량 검증(기존 FH-OFDMA 의 경우 50가입자 수용)

•  OCHM 시스템에서 16 QAM 수용시 호핑패턴 충돌에 대한 시너지/천공 제어기법의 제안과 대역효율의 개선

•  주파수와 부호의 직교자원을 활용한 OFCHM 제안, NTT DoCoMo에서 4G 시스템으로 제안한 OFCDM과 성능비교 수행, OFCHM은 패킷 지연, 패킷지연변동, 공정성 명에서 스캐줄링 방식에 비해 우위; 스캐줄링 방식과 가상전용자원할당방식과의 하이브리드 방식이 탁월한 성능을 가짐

•  OCHM의 BER 특성의 엄밀한 해석과 사용자 용량 예측

•  OCHM과 MSC 방식의 정성적 및 정량적 성능 비교

•  OCHM에서 충돌없는 그룹 개념의 제안으로 시스템 용량 개선

•  동기식 CDMA 시스템에서 부호도약을 적용시 MSC기반 시스템과의 성능 비교와 최적의 수신기 설계

•  직교자원블록 도약다중화(ORBHM) 방식을 제안하고 WiBro 시스템에서 실시간 VoIP 저속/중속 데이터 수용시 캐쥴링 방식에 대비, 제어신호의 오버헤드를 26-69% 감소,가입자 용량을 15-28% 증가 실증

기술의 독창성은 기존의 대부분의 이동통신 연구는 고속 전송기술을 스케쥴링 방식을 사용하고 있으나, 이러한 방식은 수율(throughput)은 높일 수 있으나 제어신호의 오버헤드 과다, 시스템의 복잡성, 공정성 등의 문제가 있으며, 무선 인터넷 환경에서 많이 수용될 수 있는 중저속의 무선 인터넷 데이터 트래픽을 수용하는데 절대적으로 필요한 granuality (작은 비트 속도 단위로 트래픽을 제어할 수 있는 기술)의 큰 문제를 해결하기 어려우며 데이터 트래픽의 일반적인 주요 특성인 bursty 성질을 잘 고려할 수 없다. 특히 데이터 채널 상의 활성도 (channel activity) 가 일반적으로 0.1-0.2 정도로 아주 낮으므로 이러한 트래픽을 효과적으로 수용하기 위해서는 통계적 다중화 기법이 필요한데 이 스케쥴링 방식에서는 통계적 다중화 방식을 채택하기 어렵다. 이러한 배경을 바탕으로 성교수는 스캐쥴링방식과 자원도약 기반의 가상전용자원할당방식의 하이브리드 모드 운용을 또한 제안하고 있는데, 이 때 고속과 저속 데이터 서비스를 보다 효율적으로 수행할 수 있을 것으로 사료된다. 다차원 직교자원이 주파수, 타임슬롯, 부로, 편광, 안테나 공간 등 다양하게 존재하므로 미래 새로운 통신시스템을 개발할 경우 다양한 형태의 직교자원을 활용한 직교자원블록을 정의하여 새로운 다중화/다중액세스 시스템을 설게 구현해 갈 수 있는 무궁무진한 기술로 발전해 갈 수 있을 것으로 기대하고 있다.

산업적 측면에서 OCHM/ORHM 기술 중 가장 간단한 형태의 자원 중의 하나인 직교 부호만을 도약 다중화하는 OCHM 기술을 기존의 IS-95, cdma2000, W-CDMA 시스템 등에 적용하는 경우 기존의 시스템을 크게 변경하지 않고 일부 새로운 기능 블록의 추가로 기존 시스템과 호환 (backward compatible) 가능한 기술이므로 적용상의 용이함을 가지고 있고, 한편 OCHM 기술의 Super-set에 해당하는 ORHM은 직교 부호, 주파수, 시간 및 공간에서의 포괄적인 무선 자원의 도약을 통하여 무선 자원상의 통계적 다중화 효과를 극대화하는 차세대 기술로 기대되며 학문적 측면에서도 직교 부호와 주파수, 시간 및 공간에서 주어진 무선자원의 도약(Hopping)을 통한 통계적 다중화 방식은 기존에 제안된 통신 방식의 Super set으로서의 새로운 학문 분야를 열어가는 것으로 큰 가치를 가지고 있다.

MD-ORHM(A) 관련 연구를 통하여 지금까지 7명의 박사학위와 5명의 석사학위 논문연구가 이루어졌으며, 국제저널 논문 13편과 국제학술대회 논문 20편이 발표되었으며, 총 74개의 국내외 특허가 등록되어 그 중 65개의 특허가 국내 연구소와 기업들에 기술 이전되었으며, 하이브리드 다중 액세스 기술을 IEEE 802.16m 표준화회의에 기고하였으며 이 관련 기술이 국내 기업에 이전되었다. 또한 이 관련 기술연구를 통하여 한국과학연구재단에서 개최하는 ‘이 달의 과학기술자상’을 2004년에 수상하였다.