References

References

1. T. M. Cover and A. A. El Gamal, Capacity Theorems for the Relay Channel, IEEE Transactions on Information Theory, 1979

   The foundational paper on the relay channel, introducing decode-and-forward, compress-and-forward, and the cut-set bound. Showed that DF achieves capacity for the degraded relay channel and that the gap to the cut-set bound is at most 0.5 bits for the Gaussian relay channel. The framework for all of Section 22.1.

2. J. N. Laneman, D. N. C. Tse, and G. W. Wornell, Cooperative Diversity in Wireless Networks: Efficient Protocols and Outage Behavior, IEEE Transactions on Information Theory, 2004

   The seminal paper on cooperative diversity, introducing selection relaying, space-time coded cooperation, and proving that full diversity order is achievable with single-antenna cooperating nodes. Also introduced the dynamic decode-and-forward (DDF) protocol and its optimal DMT. The primary reference for Section 22.2.

3. P. Gupta and P. R. Kumar, The Capacity of Wireless Networks, IEEE Transactions on Information Theory, 2000

   Established the fundamental scaling law $\Theta(1/\sqrt{n \log n})$ for per-node throughput in random wireless networks with multi-hop routing. One of the most cited papers in wireless networking, it defined the transport capacity concept and the protocol/physical models that have become standard analytical tools.

4. A. Ozgur, O. Leveque, and D. N. C. Tse, Hierarchical Cooperation Achieves Optimal Capacity Scaling in Ad Hoc Networks, IEEE Transactions on Information Theory, 2007

   Showed that hierarchical MIMO cooperation achieves $\Theta(1)$ per-node throughput, breaking the Gupta--Kumar barrier. Introduced the multi-level cooperative protocol that recursively forms virtual MIMO arrays of increasing size. A breakthrough result that changed the understanding of wireless network capacity limits.

5. S. C. Liew, S. Zhang, and L. Lu, Physical-Layer Network Coding: Tutorial, Survey, and Beyond, Physical Communication (Elsevier), 2013

   Comprehensive tutorial on physical-layer network coding, covering the theoretical foundations, practical implementations, and performance analysis. Includes detailed treatment of the two-way relay channel with various modulation and coding schemes. The primary reference for Section 22.4.

6. G. Kramer, M. Gastpar, and P. Gupta, Cooperative Strategies and Capacity Theorems for Relay Networks, IEEE Transactions on Information Theory, 2005

   Extended Cover--El Gamal's relay channel results to multi-relay networks, including the diamond relay channel and general relay networks. Derived cut-set bounds and DF achievable rates for networks with multiple relays, providing the theoretical foundation for multi-hop cooperative communication.

7. K. Azarian, H. El Gamal, and P. Schniter, On the Achievable Diversity-Multiplexing Tradeoff in Half-Duplex Cooperative Channels, IEEE Transactions on Information Theory, 2005

   Characterised the DMT of half-duplex cooperative channels, including the NAF (non-orthogonal AF) and DDF protocols. Showed that DDF achieves the optimal MISO DMT, while simpler protocols incur a multiplexing loss. Key reference for the DMT analysis in Section 22.2.

Further Reading

• Full-duplex relaying and self-interference cancellation

  Sabharwal, Schniter, Guo, Bliss, Rangarajan, and Wichman, "In-Band Full-Duplex Wireless: Challenges and Opportunities," IEEE JSAC, 2014

  Comprehensive survey of full-duplex wireless technology, including the self-interference cancellation techniques that enable practical full-duplex relaying. Directly extends the half-duplex analysis of this chapter to show how eliminating the half-duplex penalty changes the relay-beneficial region.

• Lattice codes for compute-and-forward

  Nazer and Gastpar, "Compute-and-Forward: Harnessing Interference Through Structured Codes," IEEE Trans. Inform. Theory, 2011

  Introduced the compute-and-forward framework using lattice codes, which provides the theoretical foundation for PNC with structured codes. Shows how interference can be harnessed rather than treated as noise, achieving rates that approach the network capacity.

• Relay selection protocols

  Bletsas, Khisti, Reed, and Lippman, "A Simple Cooperative Diversity Method Based on Network Path Selection," IEEE JSAC, 2006

  Proposed practical relay selection protocols that achieve full cooperative diversity with minimal coordination overhead. The "best relay selection" strategy requires only CSI of the relay links and achieves the same diversity order as space-time coded cooperation.

• Capacity scaling with infrastructure

  Ozgur and Leveque, "Throughput-Delay Tradeoff for Hierarchical Cooperation in Ad Hoc Wireless Networks," IEEE Trans. Inform. Theory, 2010

  Extends the hierarchical MIMO result to include delay analysis, showing the throughput-delay trade-off achievable with cooperative schemes. Essential for understanding the practical feasibility of the $\Theta(1)$ scaling result.

• IAB relaying in 5G NR

  3GPP TR 38.874: Study on Integrated Access and Backhaul

  The 3GPP study item defining integrated access and backhaul (IAB) for 5G NR, where relay nodes share spectrum between access (serving UEs) and backhaul (connecting to the core network). Provides the practical standards context for the relay protocols discussed in this chapter.