Evolution
to 4G
The radio-interface attributes for Mobile WiMAX and UMB are very similar to those of LTE. All three systems support flexible bandwidths, FDD/TDD duplexing, OFDMA in the downlink and MIMO schemes. There are a few differences such as uplink in LTE is based on SC-FDMA compared to OFDMA in Mobile WiMAX and UMB. The performance of the three systems is therefore expected to be similar with small differences. Similar to the IMT-2000 initiative, ITU-R Working Party 5D has stated requirements for IMT-advanced systems. Among others, these requirements include average downlink data rates of 100 Mbit/s in the wide area network, and up to 1 Gbit/s for local access or lowmobility scenarios. Also, at the World Radiocommunication Conference 2007 (WRC-2007), a maximum of a 428MHz new spectrum is identified for IMT systems that also include a 136MHz spectrum allocated on a global basis. Both 3GPPand IEEE 802LMSCare actively developing their own standards for submission to IMT-advanced. The goal for both LTE-advanced and IEEE 802.16m standards is to further enhance system spectral efficiency and data rates while supporting backward compatibility with their respective earlier releases. As part of the LTE-advanced and IEEE 802.16 standards developments, several enhancements including support for a larger than 20MHz bandwidth and higher-order MIMO are being discussed to meet the IMT-advanced requirements.
The radio-interface attributes for Mobile WiMAX and UMB are very similar to those of LTE. All three systems support flexible bandwidths, FDD/TDD duplexing, OFDMA in the downlink and MIMO schemes. There are a few differences such as uplink in LTE is based on SC-FDMA compared to OFDMA in Mobile WiMAX and UMB. The performance of the three systems is therefore expected to be similar with small differences. Similar to the IMT-2000 initiative, ITU-R Working Party 5D has stated requirements for IMT-advanced systems. Among others, these requirements include average downlink data rates of 100 Mbit/s in the wide area network, and up to 1 Gbit/s for local access or lowmobility scenarios. Also, at the World Radiocommunication Conference 2007 (WRC-2007), a maximum of a 428MHz new spectrum is identified for IMT systems that also include a 136MHz spectrum allocated on a global basis. Both 3GPPand IEEE 802LMSCare actively developing their own standards for submission to IMT-advanced. The goal for both LTE-advanced and IEEE 802.16m standards is to further enhance system spectral efficiency and data rates while supporting backward compatibility with their respective earlier releases. As part of the LTE-advanced and IEEE 802.16 standards developments, several enhancements including support for a larger than 20MHz bandwidth and higher-order MIMO are being discussed to meet the IMT-advanced requirements.
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