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Modified Delayed Acknowledgement for IEEE 802.15.3 Systems

This document proposes a modified delayed acknowledgement (Dly ACK) for IEEE 802.15.3 systems to improve transmission efficiency and reduce bandwidth wastage. The proposed Dly ACK allows for up to 16 bytes of acknowledgement per MSDU, providing a more efficient and reliable communication mechanism.

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Modified Delayed Acknowledgement for IEEE 802.15.3 Systems

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Modified Delayed (Dly) Acknowledgement for IEEE 802.15.3 Systems] Date Submitted: [28th June , 2004] Source: [Sanjeev K. Sharma and Jinwoo Hong] Company [Samsung Electronics] Address [75 W. Plumeria Dr, San Jose, CA, 95134] Voice:[+1-408-544-5978], FAX: [+1-408-544-5666], E-Mail:[sk.sharma@samsung.com] Re: [] Abstract: [ Modified Delayed (Dly) Acknowledgement for IEEE 802.15.3 Systems] Purpose: [For discussion to modify delayed acknowledgement in 802.15.3 Systems and include the proposed modified Dly ACK] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Sanjeev K. Sharma et al, Samsung

  2. Modified Delayed (Dly) ACK for IEEE 802.15.3 Systems July 2004 Sanjeev K. Sharma et al, Samsung

  3. Problem Definition To use Dly ACK as per current IEEE 802.15.3 MAC draft, • Each MPDU received is Delay (Dly) ACKed using 2 Bytes for each MPDU • Size of Delayed (Dly) ACK frame increases with increase in number of MPDU blocks • Larger size of 802.15.3 Delayed (Dly) ACK frame reduces the probability of its successful transmission, which may cause retransmission of all the frames causing bandwidth wastage Sanjeev K. Sharma et al, Samsung

  4. octets: 4 2 … 2 2 1 1 1 10 FCS MPDU ID block-n … MPDU ID block-2 MPDU ID block-1 MPDUs ACKed MAX Frames MAX Burst MAC header bits: b15-b9 b8-b0 Fragment Number MSDU Number Delayed (Dly) ACK in 802.15.3 • Each MPDU needs two (2) bytes for Dly ACK • Size of Dly ACK increases with increase in MPDU Blocks Figure 1: Fragmentation Control Field of IEEE 802.15.3 MAC Header Figure 2: Delayed (Dly) ACK for IEEE 802.15.3 Sanjeev K. Sharma et al, Samsung

  5. Proposed Delayed (Dly) ACK • Proposed modified Dly ACK is shown in Figure 3 • We need up to 16 bytes (128 bits as there are max 128 fragments) to Dly ACK each MSDU • First Fragment Number field is from where we want to start the Dly ACK octets: 4 octets: 4 0~16 0~16 2 2 … … 0~16 0~16 2 2 1 1 1 1 1 1 10 10 octets: 4 octets: 4 0~16 0~16 2 2 … … 0~16 0~16 2 2 1 1 1 1 1 1 10 10 Bitmap for Bitmap for Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX Bitmap for Bitmap for Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX FCS FCS MSDU n MSDU n … … MSDU 1 MSDU 1 MAC header MAC header FCS FCS MSDU n MSDU n … … MSDU 1 MSDU 1 MAC header MAC header MSDU n MSDU n MSDU 1 MSDU 1 ACKed ACKed Frames Frames Burst Burst MSDU n MSDU n MSDU 1 MSDU 1 ACKed ACKed Frames Frames Burst Burst bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 First Fragment First Fragment MSDU MSDU First Fragment First Fragment MSDU MSDU Number Number Number Number Number Number Number Number Figure 3: Proposed Modified Delayed (Dly) ACK for IEEE 802.15.3 MAC Sanjeev K. Sharma et al, Samsung

  6. 2 0~16 1 octets: 4 octets: 4 0~16 2 2 2 1 1 1 1 1 1 10 10 0~16 0~16 octets: 4 octets: 4 0~16 0~16 2 2 1 1 1 1 1 1 10 10 Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX Bitmap for Bitmap for Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX FCS FCS MSDU n MSDU 2 MSDU 1 MSDU 1 MAC header MAC header FCS FCS MSDU n MSDU n MSDU 1 MSDU 1 MAC header MAC header MSDU 1 MSDU 2 MSDU 1 MSDU 1 ACKed Frames Frames Burst Burst ACKed (19) MSDU 1 MSDU 1 Burst Burst ACKed ACKed bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 First Acked Fragment Number (50) MSDU MSDU bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 MSDU MSDU bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 Number (1) Number Number b15-b11 - b9 b10 b8 - - b0 b0 Number Number Number Number First Acked Fragment Number (0) MSDU MSDU bits: b15 bits: b7 - - b0 b9 - - b9 b9 b8 b8 - - b0 b0 MSDU MSDU bits: b15 bits: b15 - - Number (2) Number Number MSDU Number Number Number Number MSDU MSDU b00000 b111..11 Number Number b111..11 Number Number 2 bytes 1 byte Example: Multiple MSDUs (1/2) • Modified Dly ACK for Multiple MSDUs without any MSDU loss is shown in Figure 4. Delay ACKed are fragments 50~60 of MSDU1 and fragments 0~7 of MSDU2. Figure 4: To ACK Multiple MSDUs using Proposed Dly ACK Sanjeev K. Sharma et al, Samsung

  7. 2 0~16 1 octets: 4 octets: 4 0~16 2 2 2 1 1 1 1 1 1 10 10 0~16 0~16 octets: 4 octets: 4 0~16 0~16 2 2 1 1 1 1 1 1 10 10 Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX Bitmap for Bitmap for Bitmap for Bitmap for MPDUs MPDUs MAX MAX MAX MAX FCS FCS MSDU n MSDU 2 MSDU 1 MSDU 1 MAC header MAC header FCS FCS MSDU n MSDU n MSDU 1 MSDU 1 MAC header MAC header MSDU 1 MSDU 2 MSDU 1 MSDU 1 ACKed Frames Frames Burst Burst ACKed (18) MSDU 1 MSDU 1 Burst Burst ACKed ACKed bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 MSDU First Acked Fragment Number (50) MSDU bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 MSDU MSDU bits: b15 bits: b15 - - b9 b9 b8 b8 - - b0 b0 Number (1) Number Number b15-b11 - b9 b10 b8 - - b0 b0 Number Number Number Number First Acked Fragment Number (0) MSDU MSDU bits: b15 bits: b7 - - b0 b9 - - b9 b9 b8 b8 - - b0 b0 MSDU MSDU bits: b15 bits: b15 - - Number (2) Number Number MSDU Number Number Number Number MSDU MSDU b00000 b111..011 Number Number b111..11 Number Number 2 bytes 1 byte Example: Multiple MSDUs (2/2) • Modified Dly ACK for Multiple MSDUs with loss of one fragment (52) is shown in Figure 5. Delay ACKed are fragments 50~60 of MSDU1 and fragments 0~7 of MSDU2. Figure 5: To ACK Multiple MSDUs with One Lost Fragment using Proposed Dly ACK Sanjeev K. Sharma et al, Samsung

  8. Performance Comparison Table: Performance Comparison Excluding size of MAC header, Max Burst, Max Frames, and MPDUs ACKed, which is 17 bytes. Saving = (529-53)/529 89.98% Sanjeev K. Sharma et al, Samsung

  9. Advantages • We save Delay (Dly) ACK overhead significantly (up to 90%) by using the (proposed) bitmap fields. • Proposed scheme improves the throughput efficiency of the overall system. • Improves the chances of successful transmission of Dly ACK, which reduces the probability of retransmission of all frames. • In case of non-fragmented MSDUs, modified Dly ACK is identical to Dly ACK. • Easy to implement. Sanjeev K. Sharma et al, Samsung

  10. Proposal to 802.15.3b • Adopt the modified Delayed (Dly) ACK mechanism in IEEE 802.15.3b Sanjeev K. Sharma et al, Samsung

  11. References • Wireless Medium Access Control (MAC) and Physical (PHY) Layer Specifications for High Rate Wireless Personal Area Networks (WPAN), Draft P802.15.3/D17, February 2003. Sanjeev K. Sharma et al, Samsung

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