TREE-BASED TEXT ENTRY IN MESSAGING DEVICES HAVING LIMITED KEYBOARD CAPABILITY

摘要

The invention facilitates text input into a messaging device having an alphanumeric display, one or more symbol selection keys (10, 12, 14, 16), an acceptance key (18) and a rejection key (20). A plurality of messages typifying messages to be sent are accumulated. A word list is compiled containing each word occurring in at least one message, excluding misspelled words, uncommon words, etc. Each word is assigned a weighting factor representing the number of times that word occurs throughout the plurality of messages. A trie is formed with a terminal node having one entry for each letter occurring as the first letter of at least one word in the word list. Each entry contains a unique one of the first letters of the word list words and the sum of the weighting factors of all list words having that first letter. The trie's internal nodes are then formed. Initially, the display depicts all available symbols. The user manipulates the keys to select a symbol. The trie's terminal node is searched for an entry containing that symbol (i.e. letter). If there is such an entry, the trie is searched for a second level node linked to that terminal node entry. If there is such a second level node, the display is actuated to depict only symbols corresponding to letters contained in entries in that second level node, and the display's symbol selection cursor is positioned over the displayed symbol corresponding to the second level node entry having the greatest weighting factor.