{"id":1125,"date":"2011-11-13T11:04:46","date_gmt":"2011-11-13T11:04:46","guid":{"rendered":"http:\/\/www.raymaps.com\/?p=1125"},"modified":"2011-11-18T04:31:34","modified_gmt":"2011-11-18T04:31:34","slug":"cdma-vs-ofdma","status":"publish","type":"post","link":"https:\/\/www.raymaps.com\/index.php\/cdma-vs-ofdma\/","title":{"rendered":"CDMA vs OFDMA"},"content":{"rendered":"\n\n\n\n\n\n\n\n\n\n\n
Property<\/strong><\/td>\nCDMA<\/strong><\/td>\nOFDMA<\/strong><\/td>\n<\/tr>\n
1. Channel bandwidth<\/td>\nFull system bandwidth<\/td>\nVariable system bandwidth to accommodate users with different data rates, 1.25, 2.50, 5.00, 10.00, 15.00 and 20.00 MHz, actual transmission bandwidth is a bit lower than this<\/td>\n<\/tr>\n
2. Frequency-selective scheduling<\/td>\nNot possible<\/td>\nA key advantage of OFDMA, although it requires accurate real-time feedback of channel conditions from receiver to transmitter<\/td>\n<\/tr>\n
3.\u00a0Symbol period<\/td>\nVery short\u2014inverse of the system bandwidth<\/td>\nVery long\u2014defined by subcarrier spacing and independent of system bandwidth<\/td>\n<\/tr>\n
4. Equalization<\/td>\nComplicated time domain equalization<\/td>\nSimple frequency domain equalization<\/td>\n<\/tr>\n
5. Resistance to mulitpath<\/td>\nRake receiver can combine various multipath components<\/td>\nHighly resistant to multipath due to insertion of cyclic prefix (CP)<\/td>\n<\/tr>\n
6. Suitability for MIMO<\/td>\nMIMO is not suited to a wideband frequency selective channel<\/td>\nMIMO is suited to the independent narrowband flat fading channels that the subcarriers provide<\/td>\n<\/tr>\n
7.<\/strong> Resistance to narrowband interference<\/td>\nResistant to narrow band interference<\/td>\nSome subcarriers to be affected by narrowband interference<\/td>\n<\/tr>\n
8.\u00a0Separation of users<\/td>\nScrambling and orthogonal spreading codes<\/td>\nFrequency and time although scrambling and spreading can be added as well<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Reference:\u00a0Agilent 3GPP Long Term Evolution System Overview, Product Development and Test Challenges Application Note<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Property CDMA OFDMA 1. Channel bandwidth Full system bandwidth Variable system bandwidth to accommodate users with different data rates, 1.25, 2.50, 5.00, 10.00, 15.00 and 20.00 MHz, actual transmission bandwidth is a bit lower than this 2. Frequency-selective scheduling Not possible A key advantage of OFDMA, although it requires accurate real-time feedback of channel conditions from receiver to transmitter 3.\u00a0Symbol period Very short\u2014inverse of the system bandwidth Very long\u2014defined by subcarrier spacing and independent of system bandwidth 4. Equalization Complicated time domain equalization Simple frequency domain equalization 5. Resistance to mulitpath Rake receiver can combine various multipath components Highly resistant […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18,16,15],"tags":[47,31,114,51,113,112],"class_list":["post-1125","post","type-post","status-publish","format-standard","hentry","category-lte","category-wcdma","category-wimax","tag-4g","tag-fdma","tag-lte","tag-ofdm","tag-wcdma","tag-wimax"],"_links":{"self":[{"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/posts\/1125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/comments?post=1125"}],"version-history":[{"count":15,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/posts\/1125\/revisions"}],"predecessor-version":[{"id":1234,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/posts\/1125\/revisions\/1234"}],"wp:attachment":[{"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/media?parent=1125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/categories?post=1125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.raymaps.com\/index.php\/wp-json\/wp\/v2\/tags?post=1125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}