IEEE802.11e無線聯網標準

　　 
　　 在CFP中改進的信道訪問和維持輪詢向后兼容性的能力，帶來了更高效率的輪詢。另外還包括了傳輸調度和單一命令中鏈接輪詢序列的能力。
　　

　　 　　這些機制提供了最大效率的高帶寬數據流、電力管理友善實現以及對可變位速率和脈沖式數據流的輪詢式訪問。
　　
　　 　　QoS基線中采用的集中式調度器保證了避免沖突，因此，改進了傳送時間關鍵的負荷的能力。承諾重要的QoS合約（如延遲、抖動和帶寬）的能力也大為改進。信道訪問與由子網帶寬管理器（類似于更高層的協議和機制）完成的分配聯系在一起，因此獲得了更高的系統可靠性。
　　
　　 無線系統中信道的健壯性是一個重要的考慮因素，因為噪聲、干擾和多路徑效應在2.4GHz和5.xGHz頻段上導致信道吞吐量的變壞，負面地影響了對滯后敏感的和高帶寬的流量（如語音和視頻）的可靠傳輸的能力。
　　
　　 　　人們對改進信道的健壯性特別關注。提議的方案包括FEC（正向糾錯）和選擇性重發。這些機制包含了在每個數據流的基礎上制定糾錯、確認和重發政策的能力，從而通過針對每種類型數據流專門制定政策的方式，適應了多種不同的數據流類型。
　　
　　 　　通過FEC、有選擇重發的滯后確認和動態信道變化，信道的吞吐量得到大大改進。甚至在企業環境中部署了大量的無線子網時，基線的那些必進仍能支持QoS。在這樣的環境中，多個IEEE802.11e子網可能共存于各個無線電覆蓋的范圍內，在不同子網中的設備進行通信時，會引起干擾和（或）沖突。
　　
　　 　　QoS基線尚未獲得批準。在這一過程中，下一步是批準規范草案，然后是批準最終的規范。
　　
　　 Improved channel aclearcase/" target="_blank" >ccess during CFP, and the ability to retain polling for backward compatibility, result in more efficient polling. The ability to schedule transmissions and chain a sequence of polls in a single command is included.
　　
　　 These mechanisms provide for maximum efficiency for high-bandwidth streams, power-management friendly implementations, and poled-style access for variable bit rate and bursty streams.
　　
　　 The centralized scheduler used in the QoS Baseline guarantees collision avoidance and, therefore, improved ability to deliver time-critical payloads. The ability to honor critical QoS contracts such as latency, jitter and bandwidth is much improved. Channel access is tied to the allocations made by subnet bandwidth manager –like higher layer protocols and mechanisms so system reliability is achieved.
　　
　　 Channel robustness in wireless systems is an important consideration because noise, interference and multipath effects lead to degraded channel throughput in the 2.4GHz and 5.xGHz bands, adversely affecting the ability to reliably transmit latency-sensitive or high-bandwidth traffic such as voice and video.
　　
　　 Special attention was paid to improving channel robustness. The proposed schemes include FEC and selective retransmission. These mechanisms include the ability to specify the correction, the ability to specify the correction, acknowledgement and retransmission policy on per-stream basis, thereby accommodating a range of traffic types with policies designed specifically for each.
　　
　　 Channel throughput is improved through FEC, delayed acknowledgements with selective retransmissions and dynamic channel change.
　　
　　 The Baseline enhancements support QoS even when wireless subnets are deployed densely, as in enterprise environments. In such environments, multiple IEEE802.11e subnets could be located within radio range of each other, which would cause interference and/or collisions during the communications by devices in different subnets.
　　
　　 The QoS Baseline has not been approved yet. The next steps in the process are the approval of a draft specification, followed by the approval of the final specification.

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